BALTIMORE — Moments after Democrats took the debate stage on Thursday night, President Trump delivered a rambling and disjointed 68-minute speech accusing the news media and the “radical left” of wanting to destroy America.

“Whether you like me or not, it doesn’t matter,” Mr. Trump told an audience of Republican House lawmakers at a conference in Baltimore. “You have to elect me; you have no choice.” He said that a Democratic president would “take your money and very much hurt your families.”

Intended as counterprogramming to the 10 Democratic candidates debating in Houston, the president’s speech hit virtually every one of his usual political lines as he careened between prepared remarks, ad-libbed attacks and boasts about his record.

At times, Mr. Trump would read lines clearly written by a speechwriter: “Working with Republicans in Congress, we slashed 30,000 pages of regulations from the Federal Register.” But moments later, he departed from the staid lines on his teleprompter.