Welcome to The Tip Sheet, a daily political analysis of the 2018 elections, based on interviews with Republican and Democratic officials, pollsters, strategists and voters.

Where things stand

After a Trump supporter was arrested Friday, accused of mailing pipe bombs to Democrats, President Trump worried aloud that Republican “momentum” in the fall elections had stalled.

On Saturday came the Pittsburgh massacre. Mr. Trump went to an Illinois campaign rally and denounced gun violence as “evil” and called for unity, then criticized Hillary Clinton and Representative Maxine Waters (who were two targets of the pipe bomber).

It’s always difficult to know how major news events may affect an imminent election. This time is no exception, with crosscurrents of grief, faith, fear and gun politics. But two things are clear:

• Some of Mr. Trump’s lowest moments in past polls have come as he has struggled to serve in the traditional presidential role of national healer, most memorably after his “blame on both sides” response to the neo-Nazi violence last year in Charlottesville, Va.

• Mr. Trump — defiant, defensive and eager to blame the news media for his combativeness — does not seem interested in changing his approach in the final days of 2018 campaigning. His remarks on Friday and Saturday were striking for their limited empathy and for his decision to go beyond mourning and offer armchair analysis and conjecture.

“This is a case where if they had an armed guard inside, they might have been able to stop it immediately,” he said about the synagogue shootings. “Maybe there would have been nobody killed, except for him, frankly. It’s a very, very, very difficult situation, and when you look at it, you can look at it two ways.”

“You can look at it two ways” is the sort of phrase, in the immediate aftermath of deadly violence, that you rarely heard from a president before Mr. Trump.