Republicans in the newly sworn-in 115th Congress moved swiftly on Wednesday to repeal the Affordable Care Act, President Obama’s signature healthcare law. By a vote of 51 to 48, the Senate approved a procedural measure clearing a way for a budget resolution that could repeal major sections of the law. The charge was led by Vice President-elect Mike Pence, who admitted that Republicans have not yet decided how to replace the Affordable Care Act.

Vice President-elect Mike Pence: “The architecture of the replacement of Obamacare will come together, as it should, through the legislative process in the weeks and months ahead. But the American people voted for change in November, and the president-elect and I, working with the leaders of the House and Senate, are determined to keep our promise to the American people. And that all begins with repealing and replacing the failed policy of Obamacare.”

President Obama made a rare trip to Capitol Hill, where he told minority Democrats not to help Republicans pass replacement measures he called “Trumpcare.” At the White House, Press Secretary Josh Earnest said the Republican plan would have devastating consequences.

Press Secretary Josh Earnest: “Twenty-two million people are going to lose their health insurance if the Affordable Care Act is repealed. It’s going to rip a hole in the deficit, in the federal budget, and the deficit will go up, if the Affordable Care Act is repealed. That’s not just my conclusion; you can ask the CBO about that.”

Senate Republicans are seeking to end billions of dollars in federal subsidies to states that have expanded Medicaid, as well as subsidies for private health coverage through health insurance exchanges. Some provisions—like a ban on denying coverage to people with pre-existing conditions—would likely be unaffected by a repeal.