But here’s the thing: Bold, decisive campaigning only works if there are enough voters left who actually care. There’s still wiggle room in Indiana, where polls say somewhere around 6 percent of voters are undecided. But if I were one of the candidates, I’d be worried about a different figure: the percentage of people who made up their minds more than a month before the election. That number looks decidedly worse.

During elections, most exit polls ask voters how long ago they settled on their picks for president. There’s always a group that decides at the last minute, and they’re the best targets for glad-handing at the local donut shop. But there are also folks who made up their minds weeks before—even before a single candidate showed up in their state. Those voters are no longer reachable.

That particular slice of voters, which held steady for a while, has recently shot up. That makes sense: The longer the campaigns go on, the more people will have the information they need to settle on a candidate. In the last set of primaries—Pennsylvania, Maryland, Delaware, Connecticut, Rhode Island—more than half the voters had already made their picks a month before Election Day, and three-quarters knew at least two weeks before, according to CNN.