The G.O.P. presidential field is hailing the dismantling of affirmative action.

The Republicans running for president applauded the Supreme Court’s ruling on Thursday to strike down race-based affirmative action in college admissions, a policy that for decades has stoked the conservative agenda.

Former President Donald J. Trump called the decision a “great day for America” in a statement.

“People with extraordinary ability and everything else necessary for success, including future greatness for our country, are finally being rewarded,” he said, adding, “We’re going back to all merit-based — and that’s the way it should be!”

Mr. Trump’s political organization, the MAGA War Room, cast him as a main catalyst for the court’s ruling to end affirmative action, saying on Twitter that “he delivered on his promise to appoint constitutional justices.”

It also made an outlandish comparison between Mr. Trump, the Republican front-runner who has been indicted twice since leaving the White House, and Abraham Lincoln, one of the party’s iconic forebears.

“President Trump will end affirmative action like Lincoln ended slavery,” the group wrote on Twitter.

Mr. Trump appointed three of the six justices who voted to reject affirmative action at colleges, the same conservative supermajority that delivered another seismic victory for conservatives a year ago when it overturned Roe v. Wade, eliminating the constitutional right to abortion.

Mike Pence, Mr. Trump’s former vice president, who is now a 2024 rival, suggested in a statement on Thursday that he deserved a measure of credit for the court’s rightward shift and said that the “egregious” policy had “only served to perpetuate racism.”

“I am honored to have played a role in appointing three of the justices that ensured today’s welcomed decision, and as president I will continue to appoint judges who will strictly apply the law rather than twisting it to serve woke and progressive ends,” he said.

Gov. Ron DeSantis of Florida, Mr. Trump’s chief G.O.P. rival, also welcomed the court’s move.

“College admissions should be based on merit and applicants should not be judged on their race or ethnicity,” he wrote on Twitter. “The Supreme Court has correctly upheld the Constitution and ended discrimination by colleges and universities.”

Nikki Haley, the former governor of South Carolina and onetime United Nations ambassador under Mr. Trump, said in a statement that the court’s ruling had reaffirmed how Americans value freedom and opportunity.

“Picking winners and losers based on race is fundamentally wrong,” Ms. Haley said. “This decision will help every student — no matter their background — have a better opportunity to achieve the American Dream.”

Vivek Ramaswamy, a multimillionaire entrepreneur who graduated from Harvard College, which was a defendant in the Supreme Court case, pledged to take further steps to end affirmative action. In a statement, he said he would repeal a decades-old presidential executive order that requires federal contractors to adopt race-based hiring preferences.

“I’m glad the U.S. Supreme Court finally laid to rest one of the worst failed experiments in American history: affirmative action,” he said. “Still, the ruling is likely to mark the beginning of a new era of ‘shadow’ racial balancing and quotas, where elite universities like Harvard and woke employers play games to suit their desires for preferences that benefit perceived ‘marginalized’ groups.”