In 2016, despite polling showing an advantage for Democrat Hillary Clinton, voters over 65 backed Mr. Trump in the presidential election by a 52%-45% margin, according to exit polls. With still more than a year before next year’s election, 41% of seniors in a Wall Street Journal/NBC News poll in June said they would prefer to see Mr. Trump re-elected, while 48% favored a generic Democrat to win in 2020. That comes as 46% of seniors said they approve of Mr. Trump’s performance in office, slightly higher than his 44% overall approval rating…

“He’s trying to trumpet himself to the public to make them feel as good about him as he does,” said David Smith, a 69-year-old retired firefighter union president in Lancaster, Calif. “What I would like to see him do is shut his mouth.” Mr. Smith said he still would consider voting for Mr. Trump.

In a July Wall Street Journal/NBC News poll, Mr. Trump trailed former Vice President Joe Biden among seniors in a theoretical head-to-head contest, 55% to 43%. Voters over 65 also favored Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren over Mr. Trump by 7 and 8 percentage points, respectively.

“Right now, I’m a Biden man, but the only reason I am is because, according to all the polls, he could beat Trump,” said David Freund, a 65-year-old truck driver in Fort Wayne, Ind. Mr. Freund said he has voted for both Democrats and Republicans but is put off by Mr. Trump’s attitude.