The attempted assassination of Republican presidential candidate Donald J. Trump in Pennsylvania feels like a pivotal historical moment. Whether it’s a moment for the better or for the worse is an open question, though I’ve tended towards pessimism in recent years.

In a nation on the brink, with warnings of political violence in the air, the targeting of one of the two major presidential candidates is likely to exacerbate tensions. A big part of the problem is that we’ve made elections too important to lose.