With the presidential primary essentially settled, talk has already turned to who will be former Vice President Joe Biden’s running mate. But if history is any guide, we won’t know the answer for a few months.

In the modern era of presidential nominations, which began when a number of primary reforms were implemented in 1972, the presumptive presidential nominee has never announced his or her vice presidential pick before July 6. And we could be waiting much longer than that: A few running mates haven’t been announced until late August.

Running mates often get picked in late summer When each vice presidential nominee was announced, since 1972 Pres. Nominee V.P. Nominee Party Date Announced Days Before Convention McGovern Shriver* D Aug. 5, 1972 -23 Carter Mondale D July 15, 1976 0 Ford Dole R Aug. 19, 1976 0 Reagan H.W. Bush R July 17, 1980 0 Mondale Ferraro D July 12, 1984 4 Dukakis Bentsen D July 12, 1988 6 H.W. Bush Quayle R Aug. 16, 1988 0 Clinton Gore D July 9, 1992 4 Dole Kemp R Aug. 10, 1996 2 W. Bush Cheney R July 25, 2000 6 Gore Lieberman D Aug. 7, 2000 7 Kerry Edwards D July 6, 2004 20 Obama Biden D Aug. 23, 2008 2 McCain Palin R Aug. 29, 2008 3 Romney Ryan R Aug. 11, 2012 16 Trump Pence R July 15, 2016 3 Clinton Kaine D July 22, 2016 3 *Sargent Shriver replaced Thomas Eagleton as McGovern’s vice presidential pick 23 days after the 1972 Democratic National Convention ended. Mondale, Dole, H.W. Bush and Quayle were announced during their party’s convention. SourceS: News reports, library of congress

But that wide date range obscures the fact that vice presidential candidate announcements are closely tied to the timing of the party conventions — which, of course, varies every election year. Four of the vice presidential nominees since 1972 were announced at the convention, and almost all the others were announced shortly before.

For most of American history, vice presidential nominees were chosen during the conventions themselves, originally by the same chaotic, multiple-ballot process that was used to pick presidential nominees, but eventually at the direction of the presidential nominee, a trend that started with Franklin D. Roosevelt choosing Henry Wallace in 1940. And in 1984, Walter Mondale became the first presidential candidate to announce his running mate before the convention began (his pick, Geraldine Ferraro, also made history in another, more important way — she was the first woman on a major-party presidential ticket).

Since then, the No. 2 spot on the ticket has almost always been announced the week before the convention, with the median vice presidential announcement occurring four days before the convention gavels in. However, there have been some exceptions to this pattern. John Kerry revealed John Edwards as his choice on July 6, 2004 — 20 days before the Democratic convention — and Mitt Romney unveiled Paul Ryan on Aug. 11, 2012 — 16 days before the Republican conference.

This (plus failed presidential candidate Sen. Ted Cruz’s stunt of choosing businesswoman Carly Fiorina in 2016 ) could suggest it’s becoming more common for candidates to announce their running mates weeks in advance. However, Cruz’s selection was seen as a desperate ploy to resurrect his sinking presidential campaign, and Romney’s was seen as an attempt to change the narrative amid a bad news cycle, so we should probably still only expect early announcements in limited circumstances. (And considering that Biden is leading Trump in most early polls, he does not fit the historical mold of a candidate who needs to announce his choice early.)

At one point, we probably could have expected Biden’s announcement in early July, shortly before the Democratic National Convention kicked off on July 13. But the coronavirus-related delay of the convention to the week of Aug. 17 probably also pushed back the timing of the veep pick. If Biden follows the pattern of past nominees, we can probably expect to learn the identity of his running mate the week of Aug. 10. And if you’re trying to plan when exactly to track airplanes or monitor finalists’ every move, might I recommend Friday, Aug. 14? The last five vice presidential picks have all been announced either the Friday before the convention or early that Saturday morning.





FiveThirtyEight Politics Podcast: Is COVID-19 already hurting Trump politically?