Other events this summer may have bearing on the fall. The House panel investigating the attack of Jan. 6, 2021, will hold public hearings in June. Closer to the midterms, it will release its final report, which will put Republicans on the spot to answer for their defense of an attempt to overturn the results of the 2020 election. Mr. Trump will surely continue to insist the 2020 election was stolen, but most Republicans will be whipsawed between the demands of Mr. Trump and his base and their wish to focus on more winning issues.

Mr. Trump’s own behavior is exposing all the latent fissures in the contradictory coalition that narrowly elected him. Democratic candidates will be reminding Americans of the potential menace of a second Trump term. If Mr. Trump rejoins Twitter, he will remind them himself.

Even so, Republican extremism is at risk of being overshadowed by economic conditions, none more than inflation. Federal Reserve economists project that inflation could begin to subside by fall. As with so much in politics, sheer luck and timing will play a role in the Democrats’ prospects and the future of our Republic.