Donald J. Trump famously marveled during his first presidential campaign that he could shoot someone on Fifth Avenue and he would not lose any support.

He now seems intent on testing the premise of unwavering loyalty behind that statement.

The federal charges against the former president seem to have cost him few, if any, votes in the 2024 election, even as the number of Republicans who think he has committed serious federal crimes has ticked up.

He continues to hold strong in a hypothetical general election matchup, despite the fact that 17 percent of voters who prefer him over President Biden think either that he has committed serious federal crimes or that he threatened democracy with his actions after the 2020 election, according to the latest New York Times/Siena College poll.

“I think he’s committed crimes,” said Joseph Derito, 81, of Elmira, N.Y. “I think he’s done terrible things. But he’s also done a lot of good.”

Despite his distaste for the former president, Mr. Derito said he was likely to vote for Mr. Trump again. The alternative, he said, is far less palatable.

“I used to lean toward the Democratic Party because they were for the working middle class,” he said. Now, he added, “I don’t like Trump, but I like the Democrats a lot less.”

In September, just 6 percent of self-identified Republicans said Mr. Trump had committed crimes. That number in the latest poll, which was conducted before federal prosecutors added additional charges in the classified documents case, is now 13 percent.

The share of Republicans who say they are not sure whether he committed crimes has also grown, to 13 percent from 10 percent in September. In total, a quarter of Republicans either believe Mr. Trump acted criminally or say they are not sure.

So far, however, having reservations about Mr. Trump’s alleged wrongdoing does not appear to be leading Republican voters to reconsider their support for him. If anything, in public opinion polls conducted when he was indicted in March in Manhattan in relation to hush money payments to a porn star, and then when he was indicted again in June by federal prosecutors in connection with retention of reams of classified national defense material, Mr. Trump was buoyed by Republican voters.

In private conversations, Mr. Trump’s advisers have been blunt — they see the general election as vital to win in order to end the federal prosecutions against him.

The Times/Siena poll has also found that Mr. Trump is leading the field among the likely Republican primary electorate with 54 percent of the vote. The numbers illustrate the challenge for Mr. Trump’s various opponents with less than six months until the Iowa caucuses, and with the prospect that Mr. Trump may be indicted two more times before then in connection with his efforts to thwart the transfer of power after he lost the 2020 election.

Views of Mr. Trump have long been remarkably stable, and the public’s views of his potential criminality are no exception. About half of all voters say they think he has committed serious federal crimes, nearly identical to the share that held that view last year. Much like the overall public, Democrats have held firm in their views on Mr. Trump: Nearly 90 percent of Democrats consistently say they think Mr. Trump has committed serious federal crimes.

To be sure, nearly 75 percent of Republicans still say Mr. Trump did not commit any serious federal crimes. Of that group, 17 percent say they think the former president may have done something wrong in the handling of classified documents.

“He probably violated some regulation that didn’t rise to the point of a crime, or, you know, just didn’t tell somebody they were supposed to do or didn’t deliver the right paperwork,” said Henry Welch, 51, of Porter, Texas.

“It’s the federal bureaucracy,” he added. “You can violate five things without even knowing about it.”

Martin Bakri, 34, of Dayton, Ohio, said he thought it was wrong that Mr. Trump was in possession of classified documents, but that it did not concern him because he thought it was common.

“It was obvious that Biden also had some classified documents, and I’m sure they investigated half of Congress,” he said.

Mr. Trump’s supporters have repeatedly shown that they can disconnect their personal feelings about him from their vote. The former president’s overall favorability ratings have long been subpar. In 2016, many pollsters suggested he was going to lose the election in part because no presidential candidate that unpopular had ever won before. In the Times/Siena poll, 55 percent of all voters said they had an unfavorable view of Mr. Trump, including 17 percent of Republicans.

And across the Republican Party, voters say they expect fidelity to Mr. Trump in the face of his mounting legal troubles. Three-quarters of G.O.P. voters say Republicans need to stand behind him in the face of multiple investigations.

The roughly one-quarter who say Republicans do not need to stand behind Mr. Trump is largely composed of members of the party who are not open to voting for him in the primary contest, even if they may vote for him in a general election. Even a majority of the dwindling group of voters who support Gov. Ron DeSantis of Florida say Republicans need to stand behind Mr. Trump, though Mr. DeSantis has begun stepping up his attacks on his opponent’s legal challenges.

The New York Times/Siena College poll of 1,329 registered voters nationwide, including an oversample of 818 registered Republican voters, was conducted by telephone using live operators from July 23 to July 27, 2023. The margin of sampling error is plus or minus 3.67 percentage points for all registered voters. Cross-tabs and methodology are available here.

Camille Baker contributed reporting.