Welcome, class, to Conventions 101. If you’re looking for Conventions 201, you’re in the wrong place; please see Professor John Sides down the hallway. And put those cellphones away, please. We’ll get to the drama created by Ted Cruz on Wednesday night in a moment, but let’s start with the basics. For instance, as far as we’re concerned, conventions serve two major functions:
Put another way, conventions are both the official end of the nomination process and the unofficial beginning of the general election process. In the modern political era, nominations are usually decided well ahead of the conventions, so they can come to resemble extended infomercials instead.
Still, these functions can sometimes come into conflict. If you watch only the prime-time coverage of conventions, the parties generally put on a good show. But at odd hours, there can be disputes on the convention floor. Or the party will put on speakers who present red meat to the party faithful, or who fulfill obligations to party constituencies, that it wouldn’t necessarily want swing voters to see.
But modern conventions are generally successful events. They almost always produce polling “bounces” in favor of the party that just held them. These bounces can be short-lived and aren’t always predictive. Still, some part of the convention bounce usually sticks, and polls taken a few weeks after the conventions are generally much more accurate than those taken a few weeks beforehand.
At a minimum, the parties almost always succeed at converting some undecided voters, who are leaning toward the nominee but who aren’t yet fully committed, into their column. So Hillary Clinton wants to persuade straggling Bernie Sanders supporters (and there are still quite a few of them) to join her cause, and Donald Trump wants to do …