Republicans Appear Poised to Take Control of Senate, New Poll Shows

The latest polling from The New York Times and Siena College shows Republicans leading in key Senate races in Montana, Texas and Florida.

Control of the Senate appears likely to flip from the Democratic Party to the Republican Party this fall, as one of the nation’s most endangered Democrats, Senator Jon Tester of Montana, trails his Republican challenger in his bid for re-election, according to a new poll from The New York Times and Siena College.

Mr. Tester, who first won election to the Senate in 2006, is winning over moderate and independent voters and running far ahead of the Democrat at the top of the ticket, Vice President Kamala Harris. But as of now, that does not appear to be enough to survive in Montana, a conservative state where former President Donald J. Trump is ahead by 17 percentage points and where control of the Senate hangs in the balance.

Tim Sheehy, a wealthy Republican businessman and a former Navy SEAL who has never held public office, leads Mr. Tester 52 percent to 44 percent, the poll shows. Mr. Sheehy’s lead is a seven-point advantage without rounding.

Democrats currently hold a 51-seat Senate majority. But with Republicans already set to pick up a seat after the retirement of Senator Joe Manchin III, an independent from West Virginia who caucuses with Democrats, the party cannot afford to lose additional seats.

In fact, the party’s only hope is to secure a 50-50 split and to have Ms. Harris win the White House, allowing her running mate, Tim Walz, to provide the crucial tiebreaking vote as vice president.

At least seven other Democratic-held Senate seats are competitive this fall, including in the presidential battlegrounds of Arizona, Michigan, Pennsylvania, Nevada and Wisconsin. In late September, a series of Times/Siena surveys in four of those races, as well as in Ohio, found Democrats ahead, though narrowly in some cases.

[Follow the latest polls and see updated polling averages of the Harris vs. Trump matchup.]

The problem is that the Democratic Party has scarce opportunities to flip any Republican-held seats in 2024 to make up for any potential losses, such as in Montana.

The best opportunity, according to new Times/Siena polling, may be in Texas, which Democrats have long dreamed of flipping but where they have fallen well short in recent years. Senator Ted Cruz, a Republican seeking his third term, leads his Democratic challenger, Representative Colin Allred, 48 percent to 44 percent, according to a Times/Siena poll in Texas.

And in Florida, a Times/Siena poll found that Senator Rick Scott, the Republican incumbent, is comfortably ahead of Representative Debbie Mucarsel-Powell, his Democratic rival, by an even wider margin, 49 percent to 40 percent.

Both Mr. Cruz and Mr. Scott lead by smaller margins in their states than Mr. Trump is ahead of Ms. Harris.

A third potentially competitive Republican-held seat has emerged in recent weeks, though the re-election bid of Senator Deb Fischer, Republican of Nebraska, was not included in the polls. Ms. Fischer is running against an independent, Dan Osborn, and Republicans have recently come to her campaign’s aid with advertising.

In Montana, money has been flooding the state for months. With a population of around 1.1 million, Montana is set to see more than $265 million in television spending related to the Senate race, according to AdImpact, the ad-tracking service.

Republicans have circled Mr. Tester’s race as a top priority in 2024 largely because the state has become so solidly Republican in national politics. Mr. Trump won there with 57 percent of the vote in 2020 — the same percentage he was pulling in the poll.

Mr. Tester, with his flattop haircut and seven fingers — he lost three digits in a meat-grinding accident as a child — has successfully carved out a distinctive image that has long allowed him to outrun his party label and win re-election in 2012 and 2018.

This year, Republicans are hoping to make the Senate race in Montana a national partisan referendum. In the poll, 55 percent of likely voters said they would prefer that Republicans control the Senate, compared with only 37 percent who prefer Democratic control.

As of now, the poll found that Mr. Tester was winning the support of only 6 percent of Republicans. Mr. Tester trails his challenger even though he was favored over Mr. Sheehy by independent voters and viewed more favorably by them.

The race has been the top priority for Senator Steve Daines of Montana, the chairman of the Senate Republican campaign arm, the National Republican Senatorial Committee. Mr. Daines is determined to knock out his state’s senior senator. It is something of a grudge match in that Mr. Tester had vocally supported former Gov. Steve Bullock, a Democrat, when Mr. Bullock challenged Mr. Daines in 2020.

In Montana, Ms. Harris is viewed unfavorably by 60 percent of likely voters, who trusted Mr. Trump more than her on every issue tested, including the economy, immigration, abortion, democracy and helping the working class.

In a sign of the state’s partisan tilt and the uphill battle for Mr. Tester, even independent voters there said they preferred that Republicans control the Senate in 2025.

In the Montana governor’s race, Mr. Trump’s edge over Ms. Harris (57 percent to 40 percent) was similar to the lead of the Republican governor, Greg Gianforte, over his Democratic challenger, Ryan Busse (57 percent to 35 percent).

For Mr. Tester, the steady barrage of negative ads about him appears to have affected his image, with 47 percent viewing him favorably and 50 percent unfavorably.

All three new Times/Siena polls — in Montana, Texas and Florida — showed fresh evidence of a trend that has been the case across the map this year: Republican Senate candidates are running behind Mr. Trump.

In Texas, Mr. Trump was ahead by seven points, while Mr. Cruz was up by only four points.

In Florida, Mr. Trump was leading by 13 points, while Mr. Scott was ahead by nine points.

And in Montana, Mr. Trump’s lead was 10 points larger than Mr. Sheehy’s.

In all three states, the gender gap was working in the G.O.P.’s favor. Men favored the Republicans by a wider margin than women favored the Democratic candidates.

Interestingly, immigration was tied with the economy as the most pressing issue for voters in Montana — while it was significantly behind the economy as the most important issue for voters in Texas and Florida, two states that are more traditionally associated with the topic, even if Montana borders Canada.

Ruth Igielnik and Christine Zhang contributed reporting.

Here are the key things to know about these polls:

• Interviewers spoke with 656 voters in Montana from Oct. 5 to 8, 622 voters in Florida from Sept. 29 to Oct. 6, and 617 voters in Texas from Sept. 29 to Oct. 4.

• Times/Siena polls are conducted by telephone, using live interviewers, in both English and Spanish. Overall, more than 97 percent of respondents were contacted on a cellphone for these polls. 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, interviewers placed nearly 55,000 calls to nearly 30,000 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 that are underrepresented among survey respondents, like people without a college degree. You can see more information about the characteristics of respondents and the weighted sample at the bottom of the results and methodology page, under “Composition of the Sample.”

• The margin of sampling error among likely voters is about plus or minus four 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 the difference between two values is computed — 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 the Times/Siena Poll is conducted, you can see answers to frequently asked questions and submit your own questions here.