After the relatively focused early contests, the surviving candidates enter a dizzying array of primaries.  They must decide where to concentrate their efforts and resources as they jump around the country trying to hit key media markets and win enough delegates to gain the party nomination.

Overview of the Primary Process

To secure their respective parties' nominations, candidates compete in a series of state primaries and caucus/convention processes that select delegates to the national conventions.  The calendar of primaries and caucuses has been and continues to be based on the premise that several early retail contests serve to winnow the field in advance of the great mass of primaries and contests.  The theory is that the early retail contests allow even a candidate with modest funds to compete against better funded and more well known contenders.  The four early "carve out" or "pre-window" states are Iowa, New Hampshire, Nevada and South Carolina.  The Iowa caucuses and New Hampshire primary have fairly lengthy traditions, South Carolina is first in the South, and Nevada is a relatively new early state, providing for demographic and geographic balance. 

Democratic and Republican [PDF] processes unfolded from February to June 2020.  Rules governing primaries and caucuses and their timing are set out in national party rules and state laws.  Caucuses are multi-step, party run processes that generally start at the precinct level and work up through county and district levels to a state convention.  Caucuses generally have very limited participation because of the time commitment involved, and have fallen out of favor.  Several states switched from a caucus to a primary system for 2020, including Colorado, Minnesota and Washington.  Presidential preference primary elections are usually run by the state, meaning state laws apply (there are party-run primaries, but they are rare because it is expensive).  Some states hold their presidential preference primaries on different dates than the regular state primaries while in others both the presidential primary and the state primary occur on the same date.  (An early, stand-alone presidential primary can generate more presidential campaign activity, but consolidating presidential and statewide primaries on the same day saves money).  Some states allow unaffiliated voters to participate in party primaries (these are open primaries) and some do not (closed primaries).  Dates of Democratic and Republican contests generally but do not always coincide.  The two parties have different rules governing their processes.  Democratic delegates are allocated proportionally, whereas Republican rules allow for winner-take-all contests.

Most attention focused on the Democratic nominating contest, where the large number of candidates made for an uncertain outcome.  On the Republican side, President Trump had firm control of the national party infrastructure [PDF], strong backers at the helm of many state parties, scant opposition, and a solid campaign organization and delegate operation (+).  Although he was seen as all but certain to claim the nomination, the primaries and delegate selection went on according to party rules as interpreted by the RNC leadership [PDF].

March 3, 2020 was the first day for states besides the early four to hold their contests.  This was Super Tuesday, and for Democrats, the March 3 contests accounted for almost of one-third of total pledged delegates.  Most notably, California moved its presidential primary forward to March 3, and its vote by mail period began on February 3 (>); some campaigns treated California as a fifth early state. 

When one looks at the primary season as a whole, for the candidate and his or her campaign, there is always another contest a few days or a week or two away.  Working with limited resources, campaigns sometimes have to cobble together a state organization in just a few weeks, and then it is on to the next contest.  The leading candidate or candidates may be up one week and down the next.

The Rules

After each presidential election the parties review and make adjustments to their rules in hopes of setting a process for selecting a nominee in the strongest position to win the general election.  General objectives include a process that is not overly long or divisive, allows for fair competition, and encourages participation by voters and activist to build the party. 

Following their contentious 2016 primary race, Democrats established a Unity Reform Commission to "recommend improvements to insure the presidential nomination process is accessible, transparent, and inclusive."  The 21-person Commission held five meetings between May and Dec. 2017, and the full DNC approved "historic changes" to its nominating process at its summer meeting in Aug. 2018.  Most notably superdelegates—unpledged elected officials, party leaders and DNC members—who accounted for 15.0 percent of the delegates in 2016 and 16.9 percent in 2020, will not have a vote on the first presidential nominating ballot at the convention (unless the outcome is settled).  This gives grassroots Democrats a greater say in the selection of the nominee.  Other changes encourage state parties to select delegates through primaries rather than caucuses and to ensure that caucuses, when held, are accessible. 

There is always the possibility that rules changes can have unforeseen consequences.  For example, in 2008 Democrats had concerns about the divisive primary between Obama and Clinton, but one could argue that the long primary battle ultimately helped Obama by getting issues such as the controversy over Rev. Wright aired, and by allowing him to build the strong field organization and finance capabilities he took into the general election.  Following the 2008 campaign, Democrats established a Change Commission which led to rules changes increasing the number of pledged delegates by about 700 in order to dilute the impact of the superdelegates from 20 percent to 15 percent.  In advance of the 2016 campaign, Democrats reduced the number of base delegates from 3,700 to 3,200 in order to give the party a bit more flexibility in selecting a host city for its convention. 

Republicans too have adjusted their rules over the years.  At their 2014 winter meeting Republicans adopted what were termed "historic" rules changes, designed to counter shortcomings in the 2012 process.  These weaknesses included six months of candidates "slicing and dicing" each other in myriad debates, states disregarding penalties, and the several-month period between the time when the nominee was determined and when he could start spending on the general election campaign.
 

Setting the 2020 Calendar
Party rules set windows for delegate selection contests, but individual state legislatures, secretaries of state and state parties determine the specifics dates and processes.

Party Rules Set Windows for 2020 Delegate Selection Contests

No primary, caucus, convention, or other process to elect, select, allocate, or bind delegates to the national convention shall occur prior to March 1 or after the second Saturday in June in the year in which a national convention is held. Except Iowa, New Hampshire, South Carolina, and Nevada may conduct their processes no earlier than one month before the next earliest state in the year in which a national convention is held and shall not be subject to the provisions of paragraph (c)(2) of this rule. RNC Rule 16(c)(1) >

No meetings, caucuses, conventions or primaries which constitute the first determining stage in the presidential nomination process (the date of the primary in primary states, and the date of the first tier caucus in caucus states) may be held prior to the first Tuesday in March or after the second Tuesday in June in the calendar year of the national convention. Provided, however, that the Iowa precinct caucuses may be held no earlier than 29 days before the first Tuesday in March; that the New Hampshire primary may be held no earlier than 21 days before the first Tuesday in March; that the Nevada first-tier caucuses may be held no earlier than 10 days before the first Tuesday in March; and that the South Carolina primary may be held no earlier than 3 days before the first Tuesday in March. DNC Delegate Selection Rule 12(A) >

An endemic problem in the primary calendar is frontloading, wherein state party officials or legislators seek to go earlier in the process so their state will have more influence.  In past election cycles there were a few rogue states willing to violate the rules and risk penalties in order to go early.  In turn this caused the early states to move their dates even earlier.  The national party committees have sought to discourage this behavior by various incentives and penalties.  In 2012 the RNC imposed penalties on the Florida delegation that seem to have discouraged this activity.  DNC rules impose penalties for violating the timing provisions: “...the number of pledged delegates elected in each category allocated to the state pursuant to the Call for the National Convention shall be reduced by fifty (50%) percent, and the number of alternates shall also be reduced by fifty (50%) percent."  (Rule 21(C)(1.a.) - Challenges)

Democrats also tried an incentive scheme, providing for bonus delegates for states willing to go later in the process but that did not seem to have much effect.  States holding contests in April received a 10% bonus in the number of delegates, and states going in May and June received a 20% bonus.  Additionally there was an incentive to encourage regional clustering; three or more states holding contests on or after March 16, 2016 received a 15% bonus.  Republican rules have a less explicit incentive in that delegates from early state contests are allocated proportionally rather than winner-take-all.  (Rule 16(c)(2) contests "prior to March 15 in the year in which the national convention is held shall provide for the allocation of delegates on a proportional basis.")

A potential wild card in the 2020 calendar was New Hampshire Secretary of State Bill Gardner.  Gardner always waits until he is absolutely certain his state's first status will not be infringed upon before finalizing the primary date, and he assessed the impact of California's move forward and the Feb. 3 start to early voting there.  In the 2012 cycle, for example, not until Nov. 2, 2011 did Gardner announce Jan. 10, 2012 as the date of the first-in-the-nation primary, and Texas' primary date of May 29 was not set until March 1, 2012 due to legal battle over redistricting.  In the 2008 cycle (>), it took until Nov. 26, 2007 for Massachusetts Gov. Deval Patrick (D) to sign into law a measure setting the state's Feb. 5 presidential primary.  Gardner did not change the Feb. 11, 2020 date.

For Republicans, No Contest

Despite his chaotic and controversial presidency, Donald Trump was solidly positioned to be the Republican standard-bearer in 2020.  At the 2019 RNC winter meeting, members approved a resolution declaring, "The Republican National Committee hereby offers its undivided support for President Donald J. Trump and his effective Presidency."  Trump's control over the party was such that he attracted only three opponents who were not able to gain any traction.

Democrats' Crowded Field

The field of more than 20 candidates seeking the Democratic nomination in 2019-20 stood in stark contrast to 2015-16 in which the strength of former Secretary of State Hillary Clinton, long seen as the inevitable nominee, led to a small field and ultimately a two-person race with Sen. Bernie Sanders. 

Democrats' 2020 field included establishment-types and outsiders, young and old, holding views from democratic socialist to progressive to pragmatic.  The field included half a dozen women (+), several African Americans, a Latino, an Asian-American and a gay man.  Candidates brought experience in the executive branch, the U.S. Senate, the U.S. House, as governors or in other statewide offices, in local government, and in the private sector (+).  There was a 40-year spread between the youngest candidate and the oldest (+).

One wondered why such a large number of candidates, some with seemingly no hope of winning, were running.  Although the last sitting member of the U.S. House elected president was James A. Garfield in 1880, four current House members have entered the race.  About 15% of the Democratic caucus in the U.S. Senate was running.  The mayor of South Bend, a city with a population of a bit more than 102,000, was running.  One could argue that Trump upset the normal order.  Some of these candidates were no doubt thinking "if someone with Trump's set of qualifications or lack of qualifications can get elected, surely I can" or "I can do a much, much better job than this guy."  Democrats see Trump as an aberration, beatable, but, one should never underestimate Democrats' ability to "blow it."  Hillary Clinton managed that feat in 2016.  Several of the candidates seemed to be running message campaigns, rather than holding realistic thoughts of actually winning the nomination.  Another good explanation for the large field came from a Bloomberg Opinion piece by Jonathan Bernstein; he pointed to the DNC debate criteria for which "the qualifying standards were set extremely low."

The large field did create the possibility of an unexpected outcome as happened in 2016 when Trump vanquished 16 other candidates.  Into early 2020 some observers saw a possibility that none of the candidates was strong enough to secure a majority of the delegates and the race might go to the convention (>).  However, the field narrowed steadily as candidates found their messages did not resonate, did poorly at fundraising, and failed to gain traction.  The ever tightening criteria for participation in the debates furthered the winnowing process.  By the time of the first contest on Feb. 3, 2020, fifteen major Democratic candidates had ended their bids.  Others endured for one or two contests.  It is difficult to imagine how the campaign would have been conducted had the pandemic took hold a few months earlier and so many candidates were still competing.  During the Democratic primary contest, campaigns raised and spent more than $2 billion in the quest for the nomination, a figure which includes the two big self funders, Bloomberg and Steyer, but also individual contributions totaling more than $700 million to the campaigns (+).

Exiting¹the Races After the First Contest on Feb. 3:

DEMOCRATIC	< earlier exits
Andrew Yang	Feb. 11, 2020
U.S. Sen. Michael Bennet (CO)	Feb. 11, 2020
Former Gov. Deval Patrick (NH)	Feb. 12, 2020
Tom Steyer	Feb. 29, 2020
Former South Bend (IN) Mayor Pete Buttigieg	Mar. 1, 2020
U.S. Sen. Amy Klobuchar (MN)	Mar. 2, 2020
Former NYC Mayor Mike Bloomberg	Mar. 4, 2020
U.S. Sen. Elizabeth Warren (MA)	Mar. 5, 2020
U.S. Sen. Bernie Sanders (I-VT)	Apr. 8, 2020
REPUBLICAN
Former U.S. Rep. Joe Walsh	Feb. 7, 2020
Former Gov. Bill Weld	Mar. 18, 2020

Biden's strong showing in the South Carolina primary proved to be the turning point in the Democratic primary campaign.  Before South Carolina, particularly following Sanders' strong showing in Nevada, the question was "is Bernie unstoppable?"  Biden, meanwhile, had achieved only very modest showings in Iowa, New Hampshire and Nevada.  In reaction to the apparent strength of Sanders, and bolstered by the endorsement of U.S. Rep. Jim Clyburn (SC-6) and African American support, Biden finally won a contest.  In the days that followed, the former vice president received a flood of endorsements as the establishment coalesced behind him (+).  By Super Tuesday March 3 only five candidates remained, and Biden's victories on Super Tuesday cemented his position as the clear frontrunner and effectively reduced the campaign to a two-person race.  As some observers noted, the very diverse field had been reduced to two old white men.  The stage could have been set for a retake of 2016—Bernie versus the establishment.  However, by the second week of March 2020 the seriousness of the coronavirus outbreak was clear, and over the course of just a few weeks the campaign was reduced to a virtual endeavor and many states postponed presidential primaries.(+).  On April 8 Sanders suspended his campaign, vowing to work with Biden. 

Others
While the major parties get 99-percent plus of the attention, third parties are also selecting their nominees (+).  Libertarians, Greens, and the Constitution Party will run candidates in November, but none of their prospects have significant national profiles.  In addition, there was the possibility of a credible independent candidacy, although this now seems improbable.  Former Starbucks executive Howard Schultz looked into an independent run in the first part of 2019, but his effort attracted little enthusiasm. 

Turnout in the Primaries

For 2016 Pew Research Center reported that, "More than 57.6 million people, or 28.5% of estimated eligible voters, voted in the Republican and Democratic presidential primaries...close to but not quite at the record participation level set in 2008 (>)."  (Also see USEP).  In particular, Pew reported there was record turnout in a number of Republican contests due to interest in Donald Trump.  However, GOP turnout dropped markedly after the Indiana primary, when he became the presumptive nominee and only remaining candidate, going from 16.6% in the 29 primaries through Indiana to 8.4% thereafter.  Pew reported overall Democratic turnout in presidential primaries was 14.4%.  For the 2020 primaries, Democratic turnout appeared high in early contests, but coronavirus concerns as well as moves of some states to later the primary calendar will likely affect turnout.  Lack of competition on the Republican side should result in lower turnout in GOP presidential primaries.

The Calm after the Storm

During the period between the end of the primaries and the conventions, the presumptive nominee seeks to position for the general election.  Typically he or she bolsters his or her campaign organization and places key people in the national party committees to prepare for the general election.  Democrats were set to have their earliest convention since 1992, from July 13-16, but the coronavirus pandemic prompted them to push it back by about a month to the week of Aug. 17.  How effectively a presumptive nominee uses the months leading up to the convention can have important consequences on his (or her) success in the fall.
 
The March 3 Super Tuesday, March 10 mini Super Tuesday and March 17 contests, made former Vice President Joe Biden the clear frontrunner in the race for the nomination.  Biden's campaign took some early steps to pivot toward the general election.  On March 12 the campaign announced Jennifer O'Malley Dillon as campaign manager.  On March 15 the campaign announced it was adopting a couple of ideas championed by Sen. Bernie Sanders, who was still competing, and by former candidate Sen. Elizabeth Warren (+).  In the March 15 debate at CNN studios in Washington, DC Biden committed that he would pick a woman as his running mate (>). 

From mid-March the coronavirus pandemic has cast a shadow over all aspects of American life.  By April 11, the United States passed 20,000 deaths due to the virus, the most of any country, by April 25 the death toll passed 50,000 and on May 27 100,000.  Biden and his campaign have of necessity had to maintain a pretty narrow focus on that subject.  As he is not currently in office, a lot of what he is doing reacting to and critiquing President Trump.  Doubts about Biden's sometimes wobbly performance have continued (1, 2, 3).  The Trump campaign and RNC quickly highlight instances of "Joe Biden’s continued inability to communicate coherently—a sad truth that has been publicly noted by Democrats and media figures alike."  Additionally, at the end of March, Biden faced an allegation of sexual assault from Tara Reade, who worked as a staff assistant for then-Sen. Biden in 1993 (>); the campaign denied the claim and Biden himself addressed the charge in a May 1 interview on MSNBC "Morning Joe" declaring, "It did not happen.  Period. (+)"  Still, the story has not entirely gone away (>).

On other fronts, though, things were coming together for Biden.  On April 8 Sanders suspended his campaign, making Biden the presumptive nominee, and on April 13 the Vermont Senator endorsed Biden (+).  Biden has wooed Sanders' supporters and progressives on policy and on process.  On April 9 he announced proposals to lower the age for Medicare eligibility to 60 and forgive student debt for low-income and middle class families (+).  (This is somewhat counter to conventional wisdom that the presumptive nominee must move back to the center after playing to more committed or extreme elements of his or he party to win in the primaries).  On April 30 the Biden and Sanders camps announced an agreement on allocation and election of at-large and PLEO delegates and standing committee members for the Democratic National Convention (+) and on May 13 they announced leaders of six Biden-Sanders unity task forces (+).  Other former 2020 candidates are working with Biden on virtual fundraisers and other events (+).  Former President Barack Obama endorsed Biden on April 14 (+) and he has also gained the backing of 2000 nominee Al Gore (April 22) and 2016 nominee Hillary Clinton (April 28).  The DNC has built significant infrastructure to  support the Biden campaign (+), and on April 24 the campaign signed a joint fundraising agreement with the DNC including installing a new CEO at the party. 

After several months at home, Biden began to venture out in a number of low key appearances (+).  On Memorial Day he and wife Jill laid a wreath at Delaware Memorial Bridge Veterans Memorial Park.  On June 9 he met with the family of George Floyd at Lucille's Restaurant in Houston.

The period from late April to early June was seen as particularly damaging to President Trump's re-election prospects.  From the outset of the coronavirus pandemic, Trump was on the defensive about his early response and shortcomings in testing.  Trump's televised briefings did put him front and center through most of April (+).  He declared he was a "war-time president" and the ratings were good.  Ultimately episodes such as his touting of hydroxychloroquine and his musings on disinfectant (Apr. 23) undercut his case.  The "rally around the flag" effect was not evident.  In May Trump pushed for reopening the economy faster than some thought prudent, heralding a "transition to greatness" (May 8).  There were signs of trouble in the numbers, the tens of million unemployed and the 100,000 deaths (May 27), and in the tweets, where Trump still found time to push "Obamagate" theories (+), and his repeated smears of "Morning Joe" co-host Joe Scarborough were widely condemned (1, 2).  Trump's refusal to wear a mask in public, counter to public health recommendations, also drew criticism. 

The killing of George Floyd by Minneapolis police and the unrest that followed led Trump to react in one of the most poorly conceived photo ops ever on June 1, as he had Lafayette Square cleared of peaceful protestors so he could stand in front of St. John's Church holding a Bible (+).  Trump continued his "law and order" stance and Republicans sought to tie Democrats to calls by some activists to defund the police. 

The May jobs report (out June 5) provided some relatively good news.  The Trump campaign proclaimed "the great American comeback is underway" (+) and the RNC heralded the news that, "Thanks To President Trump’s Economic Leadership America Is Getting Back To Work.  Indeed, the first part of June saw many small businesses reopening, but COVID cases and deaths continued, with spikes and increases in some states.  However, the underlying reality of the situation was dire; in late July the U.S. passed four million COVID cases and 150,000 deaths from the virus.  At the end of July the Bureau of Economic Affairs reported that real gross domestic product (GDP) decreased at an annual rate of 32.9 percent in the second quarter of 2020 (+).

Bad news continued to accumulate.  Trump's hesitating walk down a ramp after speaking to cadets at West Point on June 12 led to questions about his health (+), recalling Hillary Clinton's health issues in Sept. 2016 (+).  Three unflattering books were out or en route: former National Security Advisor John Bolton's The Room Where It Happened (Simon & Schuster +, June 23) (+), neice Mary L. Trump's Too Much and Never Enough (Simon & Schuster +, July 28) and former Trump fixer/lawyer Michael Cohen's work in progress.

Throughout the ups and downs, the Trump campaign was at work.  Rapid response was fully engaged (+), fundraising remained strong (+), and each week it offered a full online broadcast schedule with something new almost every day, featuring programs such as "War Room Weekly," "Veterans for Trump Online Battle Brief" and "Blacks for Trump Real Talk Online" (+).  Trump resumed in-person fundraising at an event in Dallas on June 11 and held his first MAGA rally since March 2 in Tulsa on June 20 (+).   On July 15, the campaign announced Bill Stepien would replace Brad Parscale as campaign manager, although son-in-law Jared Kushner, a senior advisor at the White House, is said to be effectively in charge.  In early June Trump determined to move the convention away from Charlotte, but on July 23 he terminated the Jacksonville effort  in the face of spiking COVID cases in Florida (+).  Trump and the campaign have pushed back at the media (1, 2), but are operating in an environment of overwhelming skeptical/unfavorable coverage (+). 

The Biden campaign settled on a campaign message "Build Back Better."  The campaign itself remained in virtual mode, its most visible activity being many roundtables hosted by surrogates.  Biden himself has maintained a very low profile.  Meanwhile, the Trump campaign has opened field offices and is doing door knocking and actual in-person phone banks. 

In a sense this phase, the calm after the heat of the contested primaries, is also the calm before the storm.  These few months appear to augur a very rough fall campaign for Trump.

Past Campaigns
Looking at the 2016 post-primary period, the Trump campaign fell short by most measures.  He continued to provoke controversies and raise doubts about his temperament and qualifications to be president.  Quite a few prominent Republicans refused to support him.  Trump's campaign organization made some additions but remained a fraction of the size of Clinton's team.  The advertising imbalance in favor of the Democrat was staggering.  While Clinton and allies, particularly Priorities USA Action, made significant buys in battleground states, the Trump campaign itself ran no ads and allies made only minor buys.  Also in the lead up to the convention the Clinton campaign used the platform process to build bridges with the Sanders camp.

In 2012, although former Gov. Mitt Romney was seen as the frontrunner from the start of the campaign, there was a lack of enthusiasm among some Republicans, and he endured ups and downs.  Former Sen. Rick Santorum finally suspended his campaign on April 10, former Speaker Newt Gingrich suspended his campaign on May 2, and Rep. Ron Paul continued to May 14.  Romney devoted a lot of attention to fundraising, doing more than thirty fundraisers a month in May, June and August.  From June 15-19 he did a stretch of retail campaigning in an “Every Town Counts” bus tour, visiting six states that Obama carried in 2008.  A highlight of Romney's pre-convention activity was his overseas trip in late July; he travel to London for the opening ceremonies of the Olympics, and to Israel and Poland.

In 2008, on the Republican side, Sen. John McCain wrapped up the Republican nomination on March 4, leaving almost six months until the convention.  In early April McCain did a week-long "Service to America" tour designed to highlight elements of his biography; later in the month he toured "forgotten places."  McCain also did a lot of fundraising in this period.  Sen. Barack Obama took a risk in his trip to the Middle East and Europe from July 18-26.

In 2004 the calendar again led to early selection of the Democratic nominee.  Sen. John Edwards, the last major challenger to Sen. John Kerry, withdrew from the race on March 3.  In the months leading up to the convention Kerry engaged in record-breaking fundraising efforts.

In 2000 the post-primary period proved important.  Gov. George W. Bush effectively secured the Republican nomination on March 7, 2000; during late March and April he introduced a reading initiative, a plan to clean up brownfields, a "New Prosperity Initiative" to help people move from poverty to the middle class and a health care plan.  More such proposals followed in the months leading up to the convention.  For Vice President Al Gore, however, there were some bumps.  He moved his campaign headquarters to a third location and brought on a new campaign chairman, while weathering concerns about his polling numbers.  In June Gore launched a "Progress and Prosperity" tour.

For 2016, RNC chairman Reince Priebus pushed to hold a relatively early convention so that the several-month period between the time when the Republican nominee is determined and when he (or she) can start spending on the general election campaign is reduced. 

In 1996 Bob Dole had essentially won the nomination by mid-March, but he faced the period from April to the convention with virtually no funds.  In June, Dole gained much attention when he surprised everyone by resigning his Senate seat. 

In 1992 Bill Clinton used the month of June to regroup following a tough passage through the primaries.

Vice Presidential Picks

[vice presidential speculation]
An undercurrent of vice presidential speculation occurs throughout the presidential campaign cycle.  Some of the candidates running for president were widely seen by observers running not so much to win the nomination as to advance their vice presidential prospects (or even prospects for possible positions in the Cabinet).

Once a presidential candidate gains enough delegates to become the presumptive nominee, speculation on possible running mates accelerates markedly.  All sorts of rumors develop, but there is little reliable information.  Behind the scenes the campaigns do extensive vetting of vice presidential prospects, for the presumptive nominee does not want any unpleasant surprises as happened with Tom Eagleton in 1972 or the Dan Quayle choice in 1988. 

As noted above, in the March 15 debate likely Democratic nominee Joe Biden committed that he would pick a woman as his running mate (>), subsequently he elaborated on his selection process a bit (+) and on April 30 he announced Vice Presidential Selection Committee co-chairs and vetting team leaders (+). 

The likely or putative nominee weighs many factors in selecting a running mate.  The most obvious criteria is that the vice president should be capable of ascending to the presidency in the event of the unexpected.  Compatibility is an important consideration.  The vice presidential pick should also add balance to the ticket geographically, ideologically or in terms of experience. 

Various prospects enjoyed speculation boomlets in the months from April to July. Supporters advocated for one or another of the potential running mates in op-eds, open letters and petitions.  Many of the prospects did virtual events for the Biden campaign.  Biden received input from many, including key supporter U.S. Rep. Jim Clyburn, that he should choose a woman of color as his running mate.  Among the names in circulation were U.S. Sen. Kamala Harris, former national security advisor Susan Rice, U.S. Rep. Val Demings, Atlanta Mayor Keisha Lance Bottoms, U.S. Sen. Tammy Duckworth and U.S. Rep. Karen Bass.  Early on U.S. Sen. Amy Klobuchar, was see as a leading contender, in part because her moderate views aligned with those of Biden, but her stock dropped sharply after the killing of George Floyd in Minneapolis in late May.  U.S. Sen. Elizabeth Warren held a steady position in the top tier of many speculation lists.

In early 2019, as Biden considered a run, there were rumors/reports that he might select a running mate to start his campaign; the name of Stacey Abrams, the 2018 nominee for governor in Georgia, was frequently mentioned, but the rumors proved unfounded.  There have been instances in the past where a candidate still pursuing the nomination did make an early VP announcement.  The most notable example of an early VP pick occurred in 1976.  Ronald Reagan, on July 26, 1976, challenging Gerald Ford for the Republican nomination, announced that he would pair with Sen. Richard Schweiker (R-PA).  In 2016 Sen. Ted Cruz reportedly tried to form a "unity ticket" with Sen. Rubio but was rebuffed; he then selected Carly Fiorina ahead of the Indiana primary, but it did not help.  In March 2013 Bloomberg Businessweek's Joshua Green reported that Newt Gingrich and Rick Santorum had engaged in negotiations to form a "Unity Ticket" starting in early Feb. 2012, but they could not agree upon who would head the ticket.  During the 2008 primaries, there were suggestions that Sen. Clinton, trailing in the Democratic race, might try this approach. 

There is also the possibility that an incumbent president seeking re-election could decide to dump his vice president.  In 2010 there were a number of musings that President Obama might or should replace Vice President Biden.  A number of commentators suggested that he be replaced by Secretary of State Hillary Clinton, but nothing came of it.  Likewise there in 2018 there were some suggestions that President Trump might replace Vice President Pence.

In recent election cycles the VP announcement has most frequently been done a couple of days to a couple of weeks before the convention.  Keeping the announcement until shortly before the convention allows for a triumphal tour to the big gathering, draws out the period of speculation and creates further interest in the candidacy.  Often extraordinary measures are taken to keep the selection secret until the announcement.  Reporters seek information on meetings between the presumed nominee and various prospects but have little else to go on.  Speculation reaches a fever pitch; groups and activists seek to boost their favorites or discourage less favored prospects.  The campaigns send out a variety of communications to build suspense ("be the first to know").  The location of the announcement can also have significance; in many cases the presumptive nominee has opted for either a battleground state or his home state to formally introduce his or her running mate. 

Recent Vice Presidential Annoucements

			Location	Date	Conv. Start
'16	Trump	Pence	New York, NY	July 15	July 18
	Clinton	Kaine	Miami, FL	July 22	July 25
'12	Romney	Ryan	Norfolk, VA	Aug. 11 (1)	Aug. 27
'08	Obama	Biden	Springfield, IL	Aug. 23 (1, 2)	Aug. 25
	McCain	Palin	Dayton, OH	Aug. 29 (1, 2)+	Sept. 1
'04	Kerry	Edwards	Pittsburgh, PA	July 6 (1, 2)	July 26
'00	Bush	Cheney	Austin, TX	July 25	July 31
	Gore	Lieberman	Nashville, TN	Aug. 8	Aug. 14
'96	Dole	Kemp	Russell, KS	Aug. 10	Aug. 12
'92	Clinton	Gore	Little Rock, AR	July 9	July 13

Democratic Primary Calendar

Voting in a Time of Coronavirus