The Senate narrowly agreed to take up Obamacare repeal legislation Tuesday, as Majority Leader Mitch McConnell cajoled enough of his Republican colleagues to vote to move forward despite having no idea what the final bill will look like.

Without a single Democratic vote, 50 Republicans voted to begin Senate debate on a House-passed bill to repeal and replace Obamacare. That legislation — which President Trump has said is too “mean” — is not expected to survive in its current form because there will be an amendment process that will essentially replace the bill.

Sens. Lisa Murkowski of Alaska and Susan Collins of Maine both voted no, leaving Vice President Pence to cast the tie-breaking vote to approve the motion.

Sen. John McCain, who was recently diagnosed with an aggressive type of brain cancer, returned to Washington for the vote ensuring it would be a tie.

The vote is considered a win for McConnell even if it is just the first step on a steep path to repealing the health care law. Conservative and moderate senators had hinted in recent weeks that they may not support the “motion to proceed” because they were opposed to various versions of the bill the Senate was expected to proceed to.

Now that the bill has been brought to the floor, senators are expected to debate various options of repeal. Conservative Sen. Rand Paul of Kentucky – one of the Republicans who had threatened to vote against a motion to proceed — said Tuesday he has been promised that among the proposals that will get a Senate vote is a clean repeal of the Affordable Care Act by a set deadline, leaving time to figure out a plan to replace the health care law.