Sen. Jeff Flake (R-AZ) has apparently thrown his support behind the Democrat facing down the embattled Republican Roy Moore in the Alabama special election next week.

The Republican senator, who’s retiring at the end of his term in 2018, tweeted a picture of a check written out to Democratic candidate Doug Jones’s campaign for $100. On the memo line, Flake wrote “country over party.”

Country over Party pic.twitter.com/JZMTaEYdxQ — Jeff Flake (@JeffFlake) December 5, 2017

Flake stands alone as the first prominent Republican senator to back the Democrat in the Alabama Senate race, a clear break from his party, which is grappling with how to deal with Moore in the wake of sexual misconduct allegations.

Flake’s fellow Republican senators have distanced themselves from Moore after several women came forward with accusations against him, with some senators urging him to step down.

Moore has refused, leaving Republicans — as they saw it — with few viable options. It was too late to remove Moore’s name from atop the GOP ticket for the December 12 election. Republicans floated running a write-in or trying to postpone the election. Sen. Cory Gardner (R-CO), head of the National Republican Senatorial Committee, said in November that Moore should be expelled if he won — an unprecedented move.

But Republicans mostly struggled over the dilemma of how to avoid having a man accused of sexual abuse serve in the Senate while also protecting what should be a safe GOP seat. None of the solutions Republicans considered to avoid seating Moore in the Senate involved outright endorsing his Democratic opponent.

In one sense, Flake has nothing to lose by endorsing Jones. He’s not running for reelection. But while he claims he didn’t vote for Trump last year, he says he didn’t for Hillary Clinton, either. Nor did he write her a check.

His speech on the Senate floor announcing his retirement gives a clue as to why he went further in this case: “The principles that underlie our politics, the values of our founding, are too vital to our identity and to our survival to allow them to be compromised by the requirements of politics.”