When will Donald Trump make his VP pick?

Now that the presidential primaries are over, one question is on everybody's lips: Whom will Republicans nominate for vice president? Unfortunately, former President Donald Trump's campaign hasn't been cc-ing me on its internal strategy emails, so your guess is as good as mine on that one (although I recommend our recent politics chat for some informed speculation). But I might have an answer for you on when Trump will announce his running mate.

Choosing a No. 2 is a big decision - so, unsurprisingly, campaigns tend to take their time making it. Since 1972, when the modern presidential primary era began, every non-incumbent major-party presidential candidate has waited until at least July, and often August, to announce their running mate.

But we can get more specific than that. As I wrote four years ago, the timing of running-mate announcements has historically depended on when each party has held its convention. From the 1800s all the way through 1980, vice-presidential nominees were always chosen at the convention itself.* (Originally, the convention held a contested vote for vice president the same way it did for president, but things settled down in the mid-20th century, with the presidential nominee declaring his preference and the delegates going along with it.)

Then, in 1984, former Vice President Walter Mondale bucked the trend. In what was perhaps a bid to energize his struggling campaign, he tapped then-Rep. Geraldine Ferraro - the first woman on a major-party presidential ticket - as his running mate four days before the start of the Democratic National Convention. The change stuck: Since then, only one nominee (future President George H.W. Bush in 1988) has announced his running mate at the convention itself. Every other nominee has announced their running mate in the days leading up to the convention.

In fact, 11 of the last 14 non-incumbent presidential nominees have announced their running mates the week before the convention. A couple - namely, then-Sen. John Kerry in 2004 and former Massachusetts Gov. Mitt Romney in 2012 - have gone a few weeks earlier than that, but that has been rare. And like Mondale, it may have been because they wanted to shake up the campaign; both Kerry and Romney were trailing in the polls before their announcements. And let's not forget when Sen. Ted Cruz named businesswoman Carly Fiorina as his running mate in April 2016 as a last-ditch effort to seize momentum in the 2016 Republican primaries.

However, Trump is leading in the polls right now, so unless that changes, he doesn't have much of an incentive to go early. Plus, waiting until just before the convention has the added benefit of giving the nominee as much time as possible to make sure he's making the best choice.

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There's always a chance that Trump will do something unpredictable - he is Donald Trump, after all - but the most likely outcome is that he'll unveil his running mate in the week before the Republican National Convention. This year, the RNC kicks off on July 15. Dollars to donuts, we'll have an announcement between July 8 and 14.

Footnotes

*This includes then-Sen. Thomas Eagleton, whom then-Sen. George McGovern initially chose as his running mate in 1972. However, Eagleton dropped out a few weeks later after it was revealed that he had been hospitalized for depression. The Democrats' actual vice-presidential candidate that year was former Ambassador to France (and Kennedy-in-law) Sargent Shriver, whom McGovern tapped 23 days after the Democratic National Convention ended.