Trump’s Sagging Popularity Drags Down Republican Senate Candidates

“The election is a referendum on Trump,” said Kirk Adams, a Republican and former Arizona state House speaker. “That could change, but until then, down-ballot Republicans will have to decide if they will ride the Trump train to its final destination or if they need to establish some brand independence.”

Jill Cohen, a 52-year-old resident of Tempe, Ariz, who was a Republican until 2016, said she would have a difficult time supporting a Senate candidate who “aligns herself” with Mr. Trump and his views. “I look to a leader of our country to be someone who is unifying, who is welcoming, who is inclusive and who I can tell my children to look up to,” she said. Mr. Trump, she added, “is not any of those things.”

She said she longed for more consensus-oriented lawmakers and would vote for Mr. Kelly. “I really like Kyrsten Sinema for that reason because she is willing to go across the aisle and work bipartisan,” she said, referring to Arizona’s other senator. “And I think Kelly would, too.”

The margin of sampling error in the Times/Siena survey for the individual state polls in Arizona, Michigan and North Carolina is about four percentage points.

The Times survey of battleground states is not the only recent polling that illustrates how the president’s unpopularity is endangering his party’s candidates. A recent Des Moines Register poll in Iowa — which found Mr. Trump up by just one percentage point in a state he carried by about 10 in 2016 — showed Senator Joni Ernst trailing by three points against Theresa Greenfield, a first-time candidate.

Republicans have a 53-47 Senate majority. A pickup of three seats would give Democrats control, if Mr. Biden wins and his vice president is able to break a 50-50 tie. But if Doug Jones of Alabama, a rare Democratic senator in the Deep South, loses his re-election in a state that Mr. Trump is expected to comfortably carry, Democrats would need to net four seats to take control.

Yet with Republicans defending a number of competitive seats this year, the majority is now clearly within reach for Democrats. In addition to Arizona, North Carolina and Iowa, Republicans have vulnerable incumbents in Colorado and Maine, two states that Mr. Biden is favored to win.