WASHINGTON — The election of Donald J. Trump means that Justice Antonin Scalia’s seat, vacant since he died in February, will almost certainly be filled by a conservative nominee. Back to full strength, the court will again tilt right, as it has for decades.

And with the court’s two senior liberal members fairly old, that may be only the start. Justice Ruth Bader Ginsburg is 83, and Justice Stephen G. Breyer is 78.

Mr. Trump’s surprising triumph vindicates Republican senators, who refused to act on President Obama’s nomination of Judge Merrick B. Garland, saying the choice of a new Supreme Court justice should belong to the next president. It now belongs to Mr. Trump.

“Senate Republicans’ strategy of not even considering Garland, of letting the American people decide who gets to fill Scalia’s seat, worked,” said Ilya Shapiro, a lawyer with the Cato Institute, a libertarian group. “Not only that, but it didn’t at all hurt vulnerable senators running for re-election.”