Instead, they say, it will be “optimistic,” though officials caution that the ultimate delivery of the speech — and whether it follows the script that will scroll through the teleprompter — is up to Mr. Trump.

Newt Gingrich, the former Republican House speaker who has advised Mr. Trump, said the president was shifting gears, eager to promote the booming economy and the enactment of his tax plan without combative language that could muddy his message.

“They’re moving a little bit from ‘Trump the fighter’ to ‘Trump the winner,’” Mr. Gingrich said Monday. “There’s more of a sense of, ‘Look, I’m the president of the United States. I don’t need to pick a fight.’”

While some of Mr. Trump’s advisers will pine for a darker and more strident tone from the president, White House officials say they are aiming for a more inclusive speech — in tone if not in substance. In addition to Mr. Miller, the speech has been put together with Vince Haley, another speechwriter, and Rob Porter, the president’s staff secretary, who coordinated input from other parts of the government.

At the White House and among Republicans on Capitol Hill, there is a keen awareness that Mr. Trump benefits from extraordinarily low expectations of his ability to stay on message and deliver a coherent speech, given his tendency to ramble off script and insert divisive notes, insulting asides and mystifying non sequiturs that almost always overshadow the topic at hand.

Given that, officials believe, the president will be judged a success in many quarters as long as he reads faithfully from his script, resisting the urge to respond to perceived slights or settle scores and instead sticking to a positive message that can resonate with a wide swath of Americans.

“The president is looking forward to the midterm elections in November and his own election in 2020,” said Corey Stewart, a Tea Party Trump backer from Virginia who is running for Senate in the state. “He knows that he’s going to have to get his base out, but also expand it by talking about non-red meat issues.”