“The Republicans had tremendous momentum, and then, of course, this happened,” he said, adding, “Now we have to start the momentum again.”

Strategists have been divided on the durability of a so-called Kavanaugh bump in polls, bolstering Republicans in recent weeks following the fractious Supreme Court confirmation process. But there is little doubt that Republicans would prefer to focus voters’ attention there — or anywhere else, really — if the alternative is a national meditation on presidential culpability for inciting violence.

• On the campaign trail so far, Republicans are proceeding with care, if they address the bomb episodes at all.

The response from Representative Mike Coffman of Colorado, facing one of the year’s toughest re-election fights, was about as forceful as most Republicans were willing to get:

“Democrats and Republicans must come together to decry these acts of domestic terrorism and let those responsible know the intimidation of citizens, journalists and public officials will not stand,” he posted on Twitter.

Image The bombing suspect, Cesar Altieri Sayoc Jr., in a mugshot photo in Miami. Credit... Getty Images

Mr. Coffman has generally been more critical of the president’s rhetoric than others in his party, particularly when it comes to immigration. (Many people in his district are foreign-born.) But Mr. Coffman did not specifically mention the president in his tweet.