Ms. Trump, the president’s elder daughter, in particular favored the address, according to three administration officials. But the subject quickly became contentious internally, according to several administration officials. Drafts were written and rewritten, beginning around 5 p.m., with Mr. Kushner seen as in charge as the president’s chief speechwriter, Stephen Miller, wrote, and the communications office of the West Wing left out of the discussions.

By early evening, only two hours before the camera was to go on, it was still not entirely clear what Mr. Trump was going to say. In a meeting in the Cabinet Room, a number of top officials told the president the speech was a good idea, with a notable exception being the Treasury secretary, Steven Mnuchin, who said that Mr. Trump ought to wait at least a day or two so as to provide officials with more information. The president told aides gathered in the room, who disagreed on exactly how far he should go in terms of a travel ban from Europe, to come up with something and bring it to him, according to a person with direct knowledge of the events.

The health experts were either supportive of or neutral about a proposed ban on some European travelers, even as Mr. Mnuchin disagreed, and so the plan moved forward, with other items — like more specific recommendations for schools and crowds — left unmentioned.

When the camera turned on, the president appeared uncomfortable, reading words from the teleprompter in a stiff manner that made no emotional connection to a television audience of millions scared about a virus they cannot see and uncertain about a society rapidly transforming around them.

Even with the text on the screen, the president mischaracterized his own policies in a way that required his administration to correct him afterward. Administration officials said there were two errors in the teleprompter text, and one that Mr. Trump garbled as he read it, adding the word “only” in a sentence that was intended to say the ban did not apply to trade and cargo, a line that spooked markets.

He referred to the pandemic as a “foreign virus” that “will not have a chance against us” as if it were a hostile nation to be defeated on the battlefield. But while he talked about measures to prop up the economy, he did not discuss the troubles with the availability of testing kits or express understanding of the changes in everyday life affecting so many Americans.