Republican plans to quickly repeal Obamacare could be thwarted by members of the conservative House Freedom Caucus, who are threatening to block passage of the budget resolution that will allow an easy repeal the health law over fears that it might keep Obamacare taxes in place.

House Freedom Caucus Chairman Mark Meadows, R-N.C., told the Washington Examiner he is unlikely to support the resolution poised for passage in the Senate next week because of his worries about Obamacare taxes. He said his members could block it in the House by using their roughly 40-member caucus to deny the GOP majority that’s needed to pass it.