President Donald Trump meets on health care issues with Republican senators, including Sen. Susan Collins of Maine, left, and Sen. Lisa Murkowski of Alaska, in the East Room of the White House on June 27, 2017. AP file photo

When Donald Trump ran for president in 2016, U.S. Sen. Susan Collins of Maine refused to vote for him.

Denouncing him for mocking the vulnerable and attacking “ethnic and religious minorities,” she wrote in House Speaker Paul Ryan instead, a choice that did not even register in the final results since the Wisconsin Republicans had not registered as any sort of candidate in Maine.

But it appears Trump, unusually for him, is not holding a grudge.

U.S. Sen. Lindsey Graham issued a tweet recently hailing Collins, a four-term Republican, for showing “unbelievable courage” during the bitter confirmation fight last year surrounding U.S. Supreme Court Justice Brett Kavanaugh “and at other times when our country has needed a steady voice.”

“We need her to ensure a GOP majority in 2020,” Graham wrote, and urged his supporters to send money to Collins’ campaign.

Graham also linked to her recent reelection announcement.

On Monday evening, Trump retweeted Graham’s words and added a few of his own.

“I agree 100%!” Trump wrote.

It marks one of the few times Trump has directly praised Collins, who has proven a presidential ally on some key issues and a thorn in his side on others, especially in her 2017 vote to block repeal of the Affordable Care Act.

The day after her speech in favor of Kavanaugh in September 2018, Trump told reporters, “I thought that Susan was incredible yesterday.”

Collins has avoided saying anything about whether she will endorse Trump in 2020, focusing instead on what she perceives as the need to work with him on matters of national importance.

While she has not taken a stand on the presidential race next year — which is bound to have a major impact on her effort to win a fifth term — she also has not retracted any of the harsh comments she issued about Trump in a 2016 column in The Washington Post.

Collins has expressed distaste for Trump’s tweets on a number of occasions, occasionally denouncing some as over the line and sometimes simply wishing he would stop using the social media platform.

It is not clear whether Trump has ever referred to Collins so directly before on Twitter.

In 2018, he blasted a bipartisan immigration bill she cosponsored, claiming it would be “a total catastrophe” for the nation.

Generally, though, he has avoided mentioning her.

Trump has retweeted or touted U.S. Rep. Doug Collins, a Georgia Republican, dozens of times. The president has also assailed Gail Collins, a New York Times columnist, more often than he has ever referred to Maine’s senior senator.

One of the Democrats hoping to unseat Collins in Maine’s election next year, Betsy Sweet of Hallowell, wrote Tuesday on Twitter that Trump and Graham want Collins to return to the Senate in 2021 “because they know she’ll take the side of Republican special interests, not the people of Maine.”