Republicans Rally Behind Trump After Conviction, Times/Siena Poll Finds

President Biden continues to confront deeper doubts among Democrats than former President Donald J. Trump faces among Republicans — even after Mr. Trump was convicted of 34 felony charges last month, according to a new poll by The New York Times and Siena College.

The national survey on the eve of the first presidential debate shows that voters have broad distaste for both candidates but that Mr. Trump has so far better consolidated the support of his own party. Only 72 percent of voters who said they cast a ballot for Mr. Biden four years ago say they approve of the job he is doing as president. And voters overall say they now trust Mr. Trump more on the issues that matter most to them.

[You can find the full results of the polls, including the exact questions that were asked, here. You can see answers to common questions about our polling process here.]

In the first Times/Siena poll since the former president’s trial ended with a guilty verdict on May 30, more than two-thirds of voters said the outcome of his Manhattan criminal case made no difference to their vote. Roughly 90 percent of Republicans still view Mr. Trump favorably.

And among the relatively small slice who said the conviction would make a difference in their vote, Republicans said the outcome would make them likelier to support him than oppose him by a roughly 4-to-1 margin.

At the same time, the poll revealed some vulnerabilities for Mr. Trump because of his conviction, especially among independent voters who could prove decisive in November. Twice as many independents said the conviction made them more likely to oppose Mr. Trump than support him, and a majority of independents also believe he received a fair trial.

The head-to-head results of the survey show Mr. Trump with his biggest lead in a national Times/Siena poll among likely voters, 48 percent to 44 percent, a 3 percentage point margin when calculated before the figures are rounded. Mr. Trump’s lead with registered voters was an even larger 6 percentage points.

Those results are notably different than the new national polling average released by The New York Times this week, which shows Mr. Trump leading Mr. Biden by about one percentage point. It is difficult to determine whether such results, known in the polling industry as an outlier, reflect a change in public opinion not yet seen by other pollsters or are produced by random error.

In this case, the size of Mr. Trump’s lead in the poll may be related to the fact that Republicans were significantly likelier to answer their phones and take the survey than Democrats or independents, a new development in Times/Siena polling this cycle. One potential explanation was that Mr. Trump’s base is more motivated to participate in the poll after his conviction.

The candidates were neck-and-neck in the Times/Siena survey in April, with Mr. Trump holding a slight advantage — 47 percent to 46 percent — among likely voters.

In the new survey, when all four potential third-party candidates were included, Mr. Trump led Mr. Biden 40 percent to 37 percent. The independent candidate Robert F. Kennedy Jr. received 7 percent support among likely voters.

What is vivid in both this poll and across the polling average is that Americans are unhappy with the direction of the nation as Mr. Biden and Mr. Trump prepare to make their cases in a historically early debate on Thursday.

For months, Mr. Biden and his campaign had been virtually silent about the criminal charges facing Mr. Trump. But the president’s campaign has begun running advertisements in the battleground states highlighting that Mr. Trump is now a “convicted felon.”

Overall, 46 percent of registered voters said they approved of the verdict, compared to 30 percent who disapproved. The rest said they either did not have enough information or declined to say.

The poll shows that a 55 percent majority of voters — as well as 58 percent of independents and 72 percent of undecided voters — believe Mr. Trump has committed serious crimes. Notably, 18 percent of voters who said they were voting for Mr. Trump said he had committed serious federal crimes.

At the same time, 53 percent of voters — including 21 percent of Mr. Biden’s supporters — do not believe Mr. Trump should go to prison as a result of his conviction in the New York case, which centered on falsifying records to cover up a hush-money payment made to a porn star during his 2016 run. Eight percent of Mr. Trump’s supporters said he should go to prison.

There have been signs that Mr. Trump’s conviction galvanized his Republican base, including that his supporters poured $53 million into his campaign in the 24 hours after the verdict.

Colin Lietz, a 29-year-old Republican who is a logistics coordinator and who lives in Danville, Ill., said the conviction was political and hardened his support for Mr. Trump.

“I think me and a lot of people that I talk to kind of all agree that if there’s a machine out there so hellbent on destroying Donald Trump,” he said, then “that just tells you right there he’s the guy for the job.”

In the latest Times/Siena poll, Republicans were unusually eager to answer their phones and take a survey. Typically voters of both parties answer at similar rates. But in this survey, Republicans were nearly 40 percent more likely to take the survey than Democrats, a pattern that did not appear in previous Times/Siena surveys this year.

The poll still has the proper ratio of Republicans, Democrats and independents to reflect the country as a whole, but this discrepancy suggests a potential enthusiasm gap, where Trump supporters, regardless of their party, were more likely to take the survey. A similar gap was observed in 2020, but that year it was Biden supporters, who were more likely to stay at home during the pandemic, who more enthusiastically answered their phones. That phenomenon is one theory as to what caused so many polls to overstate Mr. Biden’s support that year.

The new survey shows continued reluctance to fully embrace Mr. Biden in his 2024 rematch with Mr. Trump. Last summer, 44 percent of Mr. Biden’s own supporters said they did not want him as their party’s nominee. That number has ticked up to 48 percent three months into the general election.

“Do I think it should be Biden? Probably not,” said Peta-Gaye Carby-Angus, a 35-year-old Democrat who works for a payroll company and lives in Orlando, Fla. “Do I think his intentions are in the right place? Yes, I do, and I appreciate that. But it’s like, OK, if we were to switch him out could someone else actually beat Trump? I’m not sure.”

Doubts among Trump voters about Mr. Trump as the G.O.P. nominee are far less widespread. Still, 22 percent of people who said they were voting for him said they preferred a different nominee.

Age remains a clear challenge for Mr. Biden, 81, even though Mr. Trump, 78, would also be the oldest president ever to serve if he wins.

Roughly 70 percent of voters view Mr. Biden as too old to be effective, including a majority of Biden voters. Those figures are virtually unchanged since April.

“He’s done good things in the past, but he’s too old,” Philip Hopkins, 78, a retired Democrat living in Peoria, Ariz., said of Mr. Biden.

Mr. Hopkins said he worried that the president’s age might result in a loss to Mr. Trump. “That age thing, that could cost us our freedom,” he said. “It could cost us the destruction of our country.”

In contrast, only about 40 percent of voters view Mr. Trump as too old.

Inflation and the economy continued to be the top issues for voters, and they overwhelmingly thought Mr. Trump would better handle the crucial economic concerns. Still, a rising share of voters, including a not insignificant number of Democrats, said immigration was the most important issue to them. And these voters were six times likelier to say Mr. Trump was better suited to handle the issue.

For Hispanic voters, immigration topped the economy as the most important issue. More thought Mr. Trump could better address immigration concerns.

The 8 percent of voters who said abortion was central to their vote preferred Mr. Biden over Mr. Trump. The 6 percent of voters who cited foreign policy concerns, such as the wars in Gaza or Ukraine, trusted Mr. Trump on the issue.

When asked which candidate would do better on whatever issue happened to matter most to them, 51 percent said Mr. Trump, compared to 37 percent for Mr. Biden.

Nearly identical shares of voters said Mr. Biden (47 percent) and Mr. Trump (45 percent) had the personality and temperament to be an effective president. As recently as February, more thought Mr. Biden’s temperament was better suited for the job.

Mr. Biden has regularly performed more strongly with consistent voters, and that was also true in this poll. Mr. Trump was winning 49 percent of registered voters who did not vote four years ago, compared to 30 percent for Mr. Biden.

Camille Baker contributed reporting.

Here are the key things to know about this Times/Siena poll:

• Our polls are conducted by telephone, using live interviewers, in both English and Spanish. More than 90 percent of respondents were contacted on a cellphone for this poll. You can see the exact questions that were asked and the order in which they were asked here.

• Voters are selected for the survey from a list of registered voters. The list contains information on the demographic characteristics of every registered voter, allowing us to make sure we reach the right number of voters of each party, race and region. For this poll, we placed nearly 150,000 calls to more than 100,000 voters.

• To further ensure that the results reflect the entire voting population, not just those willing to take a poll, we give more weight to respondents from demographic groups underrepresented among survey respondents, like people without a college degree. You can see more information about the characteristics of our respondents and the weighted sample on the methodology page, under “Composition of the Sample.”

• The poll’s margin of sampling error among registered voters is plus or minus three percentage points. In theory, this means that the results should reflect the views of the overall population most of the time, though many other challenges create additional sources of error. When computing the difference between two values — such as a candidate’s lead in a race — the margin of error is twice as large.

You can see full results and a detailed methodology here. If you want to read more about how and why we conduct our polls, you can see answers to frequently asked questions and submit your own questions here.