WASHINGTON ― Donald Trump attacked one of his top allies on Capitol Hill, Sen. Lindsey Graham, on Monday after the South Carolina Republican and other conservatives criticized Trump’s comments on abortion earlier in the day, in which he declined to take a position on federal legislation limiting the procedure.

“Senator Lindsey Graham is doing a great disservice to the Republican Party, and to our Country,” Trump wrote in a lengthy post on his social media website, Truth Social.

The former president went on to say that Graham “doesn’t seem to understand” that Democrats “love this issue, and they want to keep it going for as long as Republicans will allow them to do so.”

“Many Good Republicans lost Elections because of this Issue, and people like Lindsey Graham, that are unrelenting, are handing Democrats their dream of the House, Senate, and perhaps even the Presidency,” he added.

The presumptive GOP presidential nominee then urged Graham to “spend more time focusing” on the situation on the U.S.-Mexico border “and the millions of people dying in senseless, never-ending Wars he constantly favors and promotes.”

Graham is one of Trump’s biggest supporters in Congress, repeatedly defending him from criticism from Democrats and others in his own party. Graham previously introduced a bill to ban abortion after 15 weeks, which social conservatives were hoping Trump would back ahead of the November election.

In a video on Monday, however, Trump bragged about engineering a Supreme Court majority that overturned Roe v. Wade but suggested that it should be left up to the states to decide how to handle the hot-button issue, which has energized Democrats and put Republicans on the defensive.

Graham said he “respectfully” disagreed with Trump’s position and said that he would continue to advocate for a federal limit on abortions after 15 weeks, with exceptions.

He also didn’t back down when asked about Trump’s comments directly targeting him on Monday.

“The states’ rights issue, I think, is not about the pro-life movement,” Graham told HuffPost. “It’s a political position that I think doesn’t make sense if you’re pro-life, because pro-life is about the well-being of the unborn child.”

Republicans used to be far more united on federal legislation setting limits on abortion. In 2018, for example, Republican senators voted on a bill, backed by then-President Trump, that would have banned abortion after 20 weeks of pregnancy. Only two GOP senators ― Lisa Murkowski and Susan Collins ― voted with nearly every Democrat to block the measure. Trump himself called the vote “disappointing.”

Now, some of the same Republican senators who supported that bill maintain it should be left up to the states, in yet another way Trump has scrambled traditional GOP orthodoxy and forced his party into uncomfortable debates they once agreed on.

“I mean, I’d like to play in the NBA, but it’s not going to happen, OK?” Sen. John Kennedy (R-La.) told reporters on Monday about the idea of passing federal legislation to ban abortion.

“There’s no way this United States Congress is going to pass a federal rule on abortion. I mean, it’s just not,” he added. “A bill like that is dead as Dillinger, so why debate it? It’s not going to happen.”

Sen. Thom Tillis (R-N.C.) said Trump “is right” to hold off on a federal ban, adding that the rest of the GOP will now have to decide how best to approach the matter.

“It’s going to be up to the candidates to determine whether or not that may necessarily put them in a position where they disagree with the decisions of their state legislatures,” Tillis said.