Republicans are shifting their campaign focus toward the looming Supreme Court fight over replacing the late Justice Ruth Bader Ginsburg in hopes that it will inject a last-minute boost into President Trump’s reelection bid and the battle for the Senate majority.

But some in Trump’s orbit are questioning that strategy, privately fretting that the move to quickly confirm a conservative replacement for the liberal icon will backfire and energize the left in key battleground states. And behind the scenes, some Senate GOP advisers also acknowledge that this could spell bad news for at least two GOP incumbents — Susan Collins in Maine and Cory Gardner in Colorado — fighting for their political lives in Democratic-leaning states, even as they predict it could bolster other vulnerable senators.

The fears underscore the gamble Trump and Senate Majority Leader Mitch McConnell (R-Ky.) are taking as they try to refocus the electorate from the president’s ham-handed coronavirus response and toward issues that typically rally their party: Partisan Supreme Court battles recently boosted the GOP, helping Trump to victory and saving McConnell’s majority in 2016, then expanding that majority in 2018.

Among some of the president’s advisers, jitters stem from a recent internal Republican poll discussed among officials in the White House and the Trump campaign this week that contained an alarming range of signs about the vacancy, according to people who reviewed it. The poll — conducted over the weekend among about 1,500 likely voters in 17 swing states, including Arizona, Wisconsin, Florida, North Carolina and Pennsylvania — showed that 51 percent of voters said they trust Biden more than Trump to handle the vacancy, while only 43 percent said they trusted Trump.

The document also found that only 28 percent of the voters said they would be more likely to vote for Trump if a replacement is confirmed, while 38 percent said they would be less likely. And 52 percent said the Senate should hold hearings after the election, while 41 percent said it should hold hearings before the election.

At the same time, Democrats argue that the renewed interest has bolstered their own fundraising, pointing to the more than $200 million that ActBlue, the party’s online fundraising platform for small-dollar donations, has raised since Ginsburg’s death Friday. They also say the battle will sharpen their focus on health care, with the Supreme Court set to hear oral arguments in mid-November on the Trump administration’s case to strike down the Affordable Care Act, including its popular protections for people with preexisting conditions.

“I can tell you right now in our races and across the country, the number one issue for so many constituents is still the health crisis,” said Sen. Catherine Cortez Masto (D-Nev.), who leads the Democratic Senatorial Campaign Committee. “They’re going to see an administration completely ignoring the wishes of the American public during an election period for really the purpose of stacking the court, putting somebody on the court that’s going to take away their health care.”

Trump told advisers in conversations over the weekend that the Supreme Court fight was a boost for his presidential campaign and that he wanted to name a nominee before the election. His aides and allies say the Supreme Court is a fight worth having because it shows Republicans the promise of the Trump presidency, even if they disagree with his rhetoric and tactics; takes the focus off the coronavirus pandemic that has killed 200,000 Americans; and shows the president working.

“I think it’s better if you go before the election,” Trump told reporters Wednesday at the White House.” “I think it’d be fairly quick,” he said of confirmation.

Some Republicans fear injecting abortion politics into the election with the choice of judge Amy Coney Barrett — a potential vote to overturn Roe v. Wade — which could be damaging for the president and Republican senators. Indeed, the GOP polling scrutinized by the White House showed that a majority of swing-state voters wanted a justice who supports abortion rights. But there were other promising signs for the party, with one campaign adviser noting that low-dollar online fundraising was near record highs this weekend after Ginsburg’s death.

Campaign advisers also say they expect the Supreme Court pick could drive up turnout among evangelical and Catholic supporters, and the president has told advisers he believes that Democrats will overreach in the fight — giving him a target to mock.

The advisers spoke on the condition of anonymity to describe private conversations.

“Trump needs to fire up conservatives for the election. That’s the goal,” said Mike Davis, a Republican consultant who helped lead the Senate confirmation of Justice Brett M. Kavanaugh in 2018. “That is a big deal for conservatives and will motivate them.”

Josh Holmes, a longtime McConnell adviser, downplayed any polling indicating the nomination could hurt Trump and the GOP. The numbers, he said, would improve once the nominee is named and hearings begin.

“There is nothing that polling will tell me now,” he said. “When you have a live human being sitting in front of you, who is quite obviously a qualified judge, that’s a harder argument to make. The worm turns a little bit with independents.”

Overall, Senate GOP members have predicted that the court fight will reinforce their firewall and potentially help some vulnerable Republicans they had written off, even if it hurts others.

“As a matter of politics, I think recent history has clearly shown that these sorts of fights bring Republicans together, and I anticipate that will happen in 2020, just as it did in 2016 and 2018,” said Sen. Todd C. Young (R-Ind.), chairman of the National Republican Senatorial Committee. Young won in 2016 after Republicans refused to consider President Barack Obama’s last Supreme Court nominee, Merrick Garland, when they declared no justice should be confirmed eight months before the election.

Before the Ginsburg news broke, Republicans were less optimistic about holding Senate seats in Arizona and Colorado, where Sens. Martha McSally and Gardner, respectively, face tough fights. They had also begun to worry increasingly about Sen. Thom Tillis of North Carolina, who has consistently polled behind his Democratic challenger, Cal Cunningham.

Republicans now expect that Collins is more likely to join Gardner as the most endangered, because of the bluish tinge of her state. Republicans expect McSally and Tillis to get a boost, though Democrats cast doubt on those predictions.

The change of fortunes in Maine is particularly stark. For weeks, Republicans in Washington and Maine fought against Democratic proclamations that Collins — after overcoming Democratic presidential victories in the Pine Tree State in two of her four Senate wins — was finally caught in a political vise of Trump’s making. But Ginsburg’s death served as a jolt that further heightened the partisan dynamic in a state where Biden has a comfortable lead in polling, according to Democratic and GOP strategists.

The issue, some Republicans fear, will remind liberal voters of Collins’s pivotal vote to confirm Kavanaugh, which has cost her some support. Additionally, her refusal to back a Trump nominee before the election could repel the GOP base she needs to turn out, though Collins strategists say that hasn’t yet happened.

At the same time, some Republicans who initially wrote off McSally now think she has a fighting chance. It was no accident that she tweeted within minutes of the news of Ginsburg’s death that “this U.S. Senate should vote on President Trump’s next nominee for the U.S. Supreme Court.”

Those close to McSally’s campaign said she has received an increase in online donations since taking her public position, though they wouldn’t specify how much. And her allies note that the court fight will help her swing a key GOP-leaning constituency that has started to abandon Trump: conservative members of the Church of Jesus Christ of Latter-day Saints in Maricopa County.

Democratic strategists scoffed at the notion that the court fight would help McSally, who has been steadily trailing former astronaut Mark Kelly. Democrats note that after she lost her Senate race in 2018, McSally’s team put out a memo blaming the Kavanaugh court fight for her downfall.

For the GOP, the more they can turn the battleground into a red-vs.-blue dynamic, the better. Traditionally, partisan matters such as the tilt of the Supreme Court have turned out GOP voters, contributing to Trump’s surprise victory in 2016 as well as the elections of several sitting senators.

“It catapulted my race — I think Josh had the same — up to two, three points,” said Sen. Mike Braun (R-Ind.), who saw his race and that of fellow 2018 winner Sen. Josh Hawley (R-Mo.) move from a near-tie to a comfortable six-point win after the Kavanaugh confirmation clash. “And I don’t think you could have anything more comparable than what occurred back then, and it’s only been two years.”

That’s exactly what Republicans hope will happen with Tillis in North Carolina, who is already using the matter to play to his base. During a debate Monday night, Tillis sought to tie his opponent to Biden, who has declined to release a list of names of judges he would support, while touting his own support for a Trump nominee.

Democrats, however, argue that most of the fundamentals of these Senate races haven’t changed. Most voters, they say, will cast their ballots based on their feelings about Trump’s handling of the pandemic. And with voting having already started in many states, it’s unclear if there’s even enough time for the court issue to sink into the psyche, they say.

Additionally, the issue has inspired many voters to open up their wallets, they argue. Case in point: A joint-fundraising account overseen by Crooked Media, a liberal outfit founded by Obama White House alumni, raised $18.5 million in less than 72 hours after Ginsburg’s death — all for 13 Democratic candidates in key battleground states benefiting from the “Get Mitch Fund,” which uses the ActBlue portal to steer its donations.

Democrats also expect the court fight to boost their candidates in races against members of the Senate Judiciary Committee, who will oversee the confirmation process — particularly Sen. Lindsey O. Graham, the panel chairman. In South Carolina, where Graham is facing an unexpectedly strong challenge, Democrat Jaime Harrison had already raised more than $21 million in the first half of the year, a fundraising pace that has since taken off by leaps and bounds.

In Iowa, Theresa Greenfield is using a similar playbook. The Democrat taking on Sen. Joni Ernst has already made the Trump administration’s lawsuit to outlaw Obamacare a centerpiece of her campaign. And with Ernst on the Judiciary Committee, it’s another chance to highlight the vulnerable GOP incumbent’s move to try to strike down the health-care law.