A 538 video, with more to come:

By casting a ballot in a primary or caucus, voters in the U.S. have the chance to decide who will vie to lead the free world. But that wasn’t always the case. The rules governing our primary system aren’t in the Constitution, and average Americans have only been able to have their vote guaranteed to count since the 1970s. This monumental change might not have happened if it weren’t for a disastrous convention in 1968.

Over the next few weeks, we’ll be looking into how our our modern system of primaries and caucuses came to be as part of our podcast and video series, The Primary Project. This episode is about that 1968 convention, and in the following episodes, we’ll ask if the system we have today works as well as we’d like.