Former President Donald J. Trump dialed into “Fox & Friends” on Wednesday morning for his first interview since Vice President Kamala Harris picked Gov. Tim Walz of Minnesota as her running mate.

“Talk about how you’re going to handle this on the campaign trail,” the friendly Fox host Ainsley Earhardt said to the former president. “Will you just really hone in on how they voted in the past?”

It was really more of a plea than a question.

“Well, I am,” Mr. Trump assured her. “I’m going to be doing that.”

The way Republicans see it, it should not be hard for Mr. Trump to pivot from President Biden to this new Democratic ticket. All he has to do is hammer Ms. Harris and Mr. Walz for things they have said and done, to paint them as out-of-step from most Americans, on everything including policing, immigration and transgender policies.

But lately Mr. Trump keeps getting tangled up in distractions of his own making. He has gone on tangents about Ms. Harris’s biracial identity. He has picked fights with fellow Republicans. He has fantasized that Mr. Biden might somehow snatch back the nomination.

Many in Mr. Trump’s party find this all to be counterproductive, to say the least.

“The Harris-Walz ticket is the furthest left ticket in American history. They are a target-rich environment,” said Ben Shapiro, the right-wing media warrior. “All he has to do is focus the attack, to dump the war chest he’s accrued on this extremist ticket, to stick to a simple point: You were better off in 2019 than you are in 2024.”