Is it possible that the hyperpartisanship and extreme polarization that has defined American politics for the past decade may reach its apogee in this election? It’s hard to believe, and much evidence weighs against the idea. But one trend this year offers hope.

Rhetorical odes to harmony remain popular on the campaign trail. Both former President Donald Trump and Vice President Kamala Harris have presented themselves, with variable seriousness, as unifying figures, just as Joe Biden did in 2020 and throughout his presidency. Yet by most available metrics, polarization has continued to widen.

There are many reasons for that, but a big one is the modern system of closed primary elections, where only party members are eligible to vote. Adopted in the 1970s, such contests are often decided by small pools of committed partisans, heavily influenced by activist campaigns. They encourage candidates to gravitate to extreme positions, reject compromise and demonize their opponents. And once campaigns end, the real problems begin: Sane elected officials live in perpetual fear of being “primaried” by fanatics.

In some states, that could begin to change. Although little noticed amid the relentless attention on Trump and Harris, voters in Colorado, Idaho, Montana, Nevada, New Mexico and South Dakota will decide whether to adopt open primaries next week. The proposals vary, and some include ranked-choice voting, but all share a common principle: Primary ballots would include all candidates regardless of party, be open to all voters regardless of party, and allow the top finishers to advance to the general election regardless of party.

The idea isn’t new. A handful of states, both Democratic- and Republican-leaning, have already adopted it. Nor is it complicated: Open primaries change the political calculus by broadening the electorate, forcing candidates to contend with the independents and centrists who generally outnumber the ideologues, and giving competent centrists a better shot.

It probably isn’t a coincidence that of the 10 Republicans who voted to impeach Trump after the disgraceful attack on the Capitol in 2021, the only three who won reelection the next year were from states with open primaries. In one of those states, Alaska, a Democratic centrist prevailed over a favorite of the far right, Sarah Palin.

Political scientists tend to be skeptical of open primaries — many prefer stronger elite control over the nomination process — but there is empirical support for them, including evidence that, by creating more competitive contests, they increase voter turnout.

Not surprisingly, party organizations and ideological groups are trying to defeat the six ballot proposals. In Alaska, they’ve put up one of their own, to repeal the open primary that voters there adopted in 2020 — which, clearly, has worked too well.

Open primaries won’t, on their own, eradicate extremism or reverse the country’s partisan alienation. That may be a decades-long process. But if voters embrace this change on Nov. 5, it will be a victory for more sanity in campaigns and government, no matter who wins the presidency. Here’s hoping.