Sen. Susan M. Collins’ already iffy chances of reelection suffered another blow after the death of Justice Ruth Bader Ginsburg, with a new opening on the Supreme Court adding to still-simmering anger in Maine over her previous vote for Justice Brett M. Kavanaugh.
The possibility of filling Justice Ginsburg’s seat has upended Senate races from North Carolina to Arizona, giving an already deeply polarized electorate a new focal point.
Ms. Collins, a Republican, has already said she will oppose any effort by President Trump to rush a nominee through. But that may not be enough for Maine’s Democrat-leaning voters, many of whom say she bungled by voting to confirm Justice Kavanaugh in 2018.
In other states, though, Republican incumbents figure the prospect of a court battle will energize their voters, perhaps rescuing seats that had been in doubt.
“The way people look at it in, say, Susan Collins’ race in Maine is different than how it will be looked at in Tommy Tuberville’s race in Alabama and say the Colorado race with Sen. Cory Gardner,” said former Sen. George Allen, Virginia Republican. “The dynamics will be different in different states. There is no doubt about that.”
Mr. Allen said the high-stakes drama that surrounded the 2018 confirmation battle over the Kavanaugh pick could pale in comparison to fireworks to come as the Senate GOP pushes to fill the Ginsburg seat before the next Congress is sworn in.
“You can imagine what a battle royal this one is going to be,” Mr. Allen said.
The general consensus is that fights over judicial openings have done more to animate the right than the left.
Analysts said Mr. Trump’s move in the 2016 campaign to release a list of conservative names he would consider for Supreme Court openings won over some Republicans wary of their candidate, helping him secure victory over Democratic presidential nominee Hillary Clinton.
And in the 2018 midterm congressional elections, even as Democrats were rolling up big victories in the House, four incumbent Democratic senators lost their reelection bids just a month after voting against Justice Kavanaugh. Sen. Joe Manchin III, the sole Democrat to side with the GOP, won another six-year term in West Virginia.
The map is different two years later, and Democrats believe they can close that enthusiasm gap with the GOP.
“In recent years, judicial nominees have energized the Republican voters much more so than Democrats,” said Jim Manley, a Democratic strategist who as a Senate aide was part of a number of confirmation battles. “My hope this time, especially given what is at stake when it comes to such things as abortion rights and access to health care that this will drive out Democratic voters much more” than Republicans.
“Republican put all this time and attention and money toward confirming judges, while Democrats oftentimes just barely pay attention,” he said.
Activists are determined to make their base care this year, with warnings that the next court will determine whether Obamacare is struck down and the 1973 Roe v. Wade case making abortion a constitutional right remains the law of the land.
In Maine, House Speaker Sara Gideon, the Democrat challenging Ms. Collins, is making that case to voters.
“The United States Senate under Mitch McConnell’s control is virtually just rubber-stamping almost every one of Trump’s judicial nominees,” she says in a recent television ad. “They are going to affect us and our children and our grandchildren. We have to change the people who make him majority leader and that includes Sen. Susan Collins.”
Ms. Gideon says that the election could determine the direction of the Supreme Court on health care, civil rights, and reproductive rights.
Ms. Collins was a central figure in the Kavanaugh fight, which she basically ended by outlining her reasons for backing him in a memorable speech on the Senate floor.
The University of Virginia’s Center for Politics on Monday switched its prognostication for the Maine Senate race, moving it from toss-up to leaning in Ms. Gideon’s favor.
The analysts said Ms. Collins and Sen. Cory Gardner, Colorado Republican, face “an added burden” thanks to the Ginsburg seat fight.
But the analysts said the fight could “save” Sen. Lindsey Graham, a South Carolina Republican who, as chairman of the Senate Judiciary Committee, would shepherd any Trump nominee through the chamber.
It could also help candidates running in Arizona, Georgia, Iowa, Montana and North Carolina, where the electorates tend to be more Republican than the rest of the nation, they said.
“If the Court battle further polarizes the electorate and reduces ticket-splitting, that could help Republicans in the Senate,” the Center for Politics analysts said.
The opening could prove to be the nail in the coffin for Democratic Sen. Doug Jones’ reelection hopes in Alabama.
“At this point, Tuberville is the likely winner given that Trump is on the ballot,” said Sam Fisher, a political science professor at the University of South Alabama.