By Susan Cornwell

WASHINGTON (Reuters) – The U.S. Senate’s top Republican on Tuesday urged quick action on a bill to repeal Obamacare but stopped short of promising to bring it to the Senate floor for a vote, as the clock ticks down on the latest attempt to kill the 2010 healthcare law.

Mitch McConnell, the Senate’s Republican leader, called the legislation drafted by senators Lindsey Graham and Bill Cassidy “an intriguing idea and one that has a great deal of support.”

Lawmakers should act because “our opportunity to do so may well pass us by if we don’t act soon,” McConnell said on the Senate floor.

The bill has revived a fight that many in Washington thought was over when an Obamacare repeal-and-replace bill flopped in the Senate in July, humiliating McConnell and President Donald Trump.

The latest measure has less than two weeks before procedural rules in the Senate make it much more difficult for the Republicans to do away with Obamacare.

The bill proposes replacing Obamacare with a system that would give states money in block grants to run their own healthcare programs and let them opt out of some Obamacare rules. Critics say it would bring deep cuts to the Medicaid program for the poor and higher insurance premiums for older people.

“Graham-Cassidy would be devastating for individuals with pre-existing conditions,” the Center for American Progress, a liberal think tank in Washington, said in a statement.

McConnell stopped short of promising to bring the legislation to the Senate floor. But he said Republican lawmakers would continue to discuss it. He has been meeting with lawmakers to assess whether the bill has the votes to pass.

The proposal is the latest salvo in a long-running Republican war on Obamacare, and Graham and Cassidy say they are close to securing the votes needed for passage.

If approved, it would replace the 2010 Affordable Care Act, known informally as Obamacare, which Republicans have long seen as government overreach into the healthcare business.

Several Republicans – the same ones whose votes blocked repeal of Obamacare in July – are still undecided on the latest bill and time is running out.

A special parliamentary procedure that would allow the bill to move forward with only 51 votes will expire at the end of the month. After that, it would need 60 votes, like most Senate legislation. Republicans have a 52-vote Senate majority.

The Senate Finance Committee said it will hold a hearing on the bill next week.

If the Senate can pass the bill, “the hope would be that the House would take it up and pass it and the president sign it,” said John Cornyn, the No. 2 Senate Republican.

Senate Democratic Leader Chuck Schumer said Republicans were “grossly irresponsible” to consider legislation before even getting a full assessment of its impacts from the non-partisan Congressional Budget Office.

(Additional reporting by Richard Cowan and Amanda Becker; Editing by Chizu Nomiyama and Alistair Bell)