Senator Susan Collins (R-ME) walks to the Senate floor ahead of a vote on the health care bill on Capitol Hill in Washington, US, July 27, 2017. [Photo/Agencies]

WASHINGTON — The last-gasp Republican drive to tear down President Barack Obama's health care law essentially died Monday as Maine Sen. Susan Collins joined a small but decisive cluster of GOP senators in opposing the push.

The Maine moderate said in a statement that the legislation would make "devastating" cuts in the Medicaid program for poor and disabled people, drive up premiums for millions and weaken protections Obama's law gives people with pre-existing medical conditions. She said the legislation is "deeply flawed," despite eleventh-hour changes its sponsors have made in search of support.

The only way Republicans could resuscitate their push would be to change opposing senators' minds, which they've tried unsuccessfully to do for months. Collins told reporters that she made her decision despite a phone call from President Donald Trump, who's been futilely trying to press unhappy GOP senators to back the measure.

"They're still working it and a lot of conversations are going on," No 3 Senate GOP leader John Thune of South Dakota told reporters. But he conceded that a revival would be "a heavy lift" and the prospects were "bleak."The collapse marks a replay of the embarrassing loss Trump and party leaders suffered in July, when the Senate rejected three attempts to pass legislation erasing Obama's 2010 statute. The GOP has made promises to scrap the law a high-profile vow for years, and its failure to deliver despite controlling the White House and Congress has infuriated conservatives whose votes Republican candidates need.

Republicans had pinned their last hopes on a measure by GOP Sens. Bill Cassidy of Louisiana and South Carolina's Lindsey Graham. It would end Obama's Medicaid expansion and subsidies for consumers and ship the money — $1.2 trillion through 2026 — to states to use on health services with few constraints.

With their narrow 52-48 majority and solid Democratic opposition, three GOP "no" votes would doom the bill. GOP Sens. John McCain of Arizona, Rand Paul of Kentucky and Texas' Ted Cruz have said they oppose the measure, though Cruz aides said he was seeking changes that would let him vote yes.

Sen. Lisa Murkowski, R-Alaska, remains undecided. Murkowski, who voted against the failed GOP bills in July, has said she's analyzing the measure's impact on her state, where medical costs are high.

The Senate must vote this week for Republicans to have any chance of prevailing with their narrow margin. Next Sunday, protections expire against a Democratic filibuster, bill-killing delays that Republicans lack the votes to overcome.