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...