Blindsided by the latest collapse of a Republican health care bill, President Trump took to Twitter to voice his frustration. Trump complained of being "let down" by a handful of Republican lawmakers. And he insisted that the fight over the Affordable Care Act, also known as Obamacare, is not over.

Trump had just finished discussing health care with seven Republican lawmakers over dinner Monday when Sens. Mike Lee, R-Utah, and Jerry Moran, R-Kansas — who were not at the meeting — announced they would be voting against the measure to repeal and replace Obamacare. With two other Republican senators already on record in opposition, the Monday-night development effectively killed the Senate bill.

Trump acknowledged he was caught off guard by the latest GOP defections.

"For seven years, I've been hearing repeal and replace from Congress," Trump said. "And then when we finally get a chance to repeal and replace, they don't take advantage of it. So that's disappointing."

The White House dinner was part of a low-key and ultimately unsuccessful lobbying effort by the president. Press secretary Sean Spicer insists Trump was actively working for the bill's passage, even though he spent much of the weekend watching the U.S. Women's Open golf tournament at his Bedminster, N.J., resort.

"He's been extremely engaged throughout the weekend, making phone calls, talking to folks, meeting with his team, getting updates," Spicer said.

Trump also spent valuable time on Monday at a White House event designed to showcase domestic manufacturing. He posed for pictures behind the wheel of a gleaming fire engine built by Pierce Manufacturing of Wisconsin. By coincidence, the White House had staged a similar photo-op with the president at the end of March, the day before a different Obamacare replacement bill died in the House.

The president is now encouraging Senate Republicans to simply repeal the Affordable Care Act, leaving any discussion of a replacement for a later date. That idea already appears doomed, as at least three GOP senators have come out against it.

The Senate passed a repeal bill in 2015, but it was vetoed by then-President Barack Obama. The Congressional Budget Office warned in January that repealing Obamacare without a replacement would be highly destabilizing for the individual insurance market, leaving 32 million more Americans without health coverage within a decade. (That's significantly more than the uninsured projections for Republican House and Senate replacement bills.)

The president has repeatedly said that Congress must do something to avoid a health care meltdown.

"Obamacare is a big failure and it has to be changed," he told reporters Tuesday. "I'm not going to own it. I can tell you the Republicans are not going to own it. We'll let Obamacare fail and then the Democrats are going to come to us and they're going to say, 'How do we fix it?'"

Researchers at the Kaiser Family Foundation dispute that ominous picture. They argue the individual insurance market is stabilizing in most parts of the country, although deliberate moves by the administration could undermine that. NPR's Danielle Kurtzleben made the same point in March.

Under the Senate's procedural rules, Republicans can't repeal all of the Affordable Care Act with a simple majority. It takes at least 60 votes, for example, to repeal the provision requiring insurance companies to cover everyone. Leaving that piece in place while doing away with the requirement that all Americans have insurance could trigger a sharp spike in premiums.

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