(CNN)The Republican Party’s efforts to gut former President Barack Obama’s legacy health care law came to an abrupt — if temporary — halt Monday night.

Just hours after the Senate was gaveled back into session, Senate Majority Leader Mitch McConnell was handed two more public defections on his health care bill to overhaul Obamacare. The dramatic and simultaneous announcement from Sens. Jerry Moran of Kansas and Mike Lee of Utah means McConnell officially does not have the votes to even begin debate on his legislation to overhaul the Affordable Care Act.

How the Republican health care bill fell apart
How the Republican health care bill fell apart

The development deals a devastating blow not only to Republicans who have railed against the law for years, but also President Donald Trump, who campaigned on killing Obamacare and made repealing the law his top legislative priority since taking office.

“Regretfully, it is now apparent that the effort to repeal and immediately replace the failure of Obamacare will not be successful,” McConnell said in a statement late Monday. He said the Senate would vote in the coming days on a bill that would delay the repeal of Obamacare for two years — all as Trump called for a wholesale repeal of the law.

90s clinton health care reform RON_00010111.jpg
The last time health care reform failed

In announcing their opposition to the bill, Moran and Lee said they would vote “no” on the motion to proceed — a vote that McConnell had hoped to hold this week but was already forced to postpone due to Arizona Sen. John McCain’s unexpected absence from Washington.

“We should not put our stamp of approval on bad policy. Furthermore, if we leave the federal government in control of everyday healthcare decisions, it is more likely that our healthcare system will devolve into a single-payer system, which would require a massive federal spending increase,” Moran said in a statement.

The surprise announcement was all the more devastating as Trump was trying to shore up support for the bill at a dinner at the White House. The group of attendees included Sens. Richard Shelby of Alabama, Steve Daines of Montana and James Lankford of Oklahoma. The three, like Moran, are reliably conservative senators who generally vote with McConnell on major bills.

After Moran and Lee’s announcement, Trump tweeted, “Republicans should just REPEAL failing ObamaCare now & work on a new Healthcare Plan that will start from a clean slate. Dems will join in!”

On Tuesday morning Trump returned to Twitter: “We were let down by all of the Democrats and a few Republicans. Most Republicans were loyal, terrific & worked really hard. We will return!”