A top conservative group is threatening primary challenges to senators who vote against a repeal of ObamaCare after Senate Republicans failed to coalesce around a replacement plan.

Former Virginia Attorney General Ken Cuccinelli, who now serves as the president of the Senate Conservatives Fund, drew the line in the sand on Tuesday, soon after reports surfaced that Senate Majority Leader Mitch McConnell Addison (Mitch) Mitchell McConnellOcasio-Cortez to voters: Tell McConnell 'he is playing with fire' with Ginsburg's seat McConnell locks down key GOP votes in Supreme Court fight Video shows NYC subway station renamed after Ruth Bader Ginsburg MORE (R-Ky.) plans to hold a repeal vote even though it's already clear he doesn't have the votes to pass it.

"Republicans have promised to repeal Obamacare for years and now with President Trump in the White House, there is no excuse for them to break their promise," Cuccinelli said.

"Working with the grassroots across the country, we will seek to identify, recruit, and fund conservative challengers against Republican senators who vote against repeal. If they won’t keep their word and if they can’t find the courage to repeal a liberal takeover of our health care system that has hurt so many American families, they should be replaced by someone who will.”

None of them are up for reelection in 2018 — Collins and Capito are up again in 2020, while Murkowski doesn't have to worry about reelection until 2022.