NEW YORK — Nothing could have shifted the political landscape more than this.

Supreme Court Justice Anthony Kennedy's retirement and President Donald Trump's pledge to move quickly to fill the seat guarantee a searing summer of charged rhetoric that could touch on virtually every hot-button social and cultural issue in American politics.

The news was especially deflating for Democrats who felt immediate flashbacks to the 2016 presidential election, when the tantalizing prospect of an open Supreme Court seat spurred some GOP voters to back Trump even if they found him personally objectionable.

It was a dramatic shift for Democrats who had been optimistic about seizing the House majority, if not the Senate. Some of the most dejected responded on social media with obscenities. Others teased a political strategy by warning of severe consequences for health care and abortion rights should Trump have his way.

But for Republicans, who have feared a massive enthusiasm advantage for Democrats, the sudden vacancy that could shape the court's direction for a generation was nothing short of a gift from the political gods. In addition to a massive dose of energy, the Supreme Court fight is expected to trigger a flood of new campaign cash that will strengthen the GOP's midterm efforts.

"It's a game-changer," said Republican strategist Chris Wilson. "There's no piece of legislation, no executive order, no Supreme Court decision that would have created the level of motivation that an empty seat does."

Indeed, a similar scenario played out in 2016 and, two years later, the strategy is proving successful for Republicans. Trump's first pick for the Supreme Court, Neil Gorsuch, helped uphold the president's ban on travel from several mostly Muslim countries this week. Gorsuch and his fellow conservatives delivered on another GOP priority Wednesday in a decision that will deal a serious financial blow to Democratic-leaning organized labor.

Trump now has a chance to nominate a second justice who could cement the court's conservative bend and deliver Republican victories for years to come.

The political focus shifts immediately to the Senate, where 10 Democrats running for re-election in states Trump carried in 2016 will soon have to weigh in on the vacancy.

Three of the most vulnerable Senate Democrats — North Dakota's Heidi Heitkamp, West Virginia's Joe Manchin and Indiana's Joe Donnelly — voted in favor of Gorsuch last year. They will face enormous pressure from both parties as they grapple with the president's next pick.

Some Senate Democratic contenders in GOP-leaning states saw this as an opportunity to distance themselves from the national party. In Tennessee, Democratic Senate nominee Phil Bredesen immediately embraced the opportunity for centrism, using the Supreme Court vacancy to bolster his argument that he'd be an independent voice amid partisan rancor, a key point the former governor makes repeatedly as he tries to upset GOP Rep. Marsha Blackburn.

"Not long ago, Senate confirmation was free of openly partisan politics," Bredesen says in a 30-second ad that his campaign says was already cut in anticipation of Kennedy's retirement. They're posting the spot, obtained by The Associated Press, online later Wednesday and may put it on television in coming weeks.

Still, Republicans, who have been struggling to energize their voters, now get a powerful persuader.

"It's going to be a huge plus for Republican candidates in terms of answering that easy but sometimes difficult question: Why me? Why now?" said Republican strategist Andrea Bozek, who is working with several Republican candidates this cycle. "It makes the case very real on why we need to maintain and grow the Republican majority in the Senate."

Added Republican pollster Frank Luntz: "Now all the marbles are on the Senate."

The conservative Koch brothers' political arm, Americans For Prosperity, promised to invest seven figures in a broader campaign to support Trump's pick on the ground in key states, according to spokesman James Davis.

"Obviously, we're looking at the nominee first. We want another nominee who's principled, who's going to follow the rule of law similar to Justice Gorsuch," Davis said. "Then we'll launch immediately."

There was immediate pressure on Senate Minority Leader Chuck Schumer of New York to use all the tools at his disposal to stop Trump from filling a vacancy. But with the elimination of the filibuster on Supreme Court nominees, he doesn't have much leverage beyond rhetoric and unifying his party, forcing Senate Majority Leader Mitch McConnell to supply the votes.