Millions of Americans could lose health insurance under Trump megabill, CBO estimates

The "One Big Beautiful Bill Act" -- a massive tax and immigration bill to fund much of President Donald Trump's agenda -- could add $2.4 trillion to the deficit over the next decade, according to a new analysis out Wednesday from the nonpartisan Congressional Budget Office.

The CBO released updated estimates on the legislation as focus turned to the Senate, where a handful of Republican members are expressing concerns about the deficit and changes to Medicaid.

The budget office is projecting 10.9 million more people will be uninsured in 2034 because of changes to Medicaid included in the Trump megabill.

The CBO projects overall a total of 16 million people could potentially go uninsured over the next decade, due to 5.1 million who could lose coverage due to new Affordable Care enrollment rules and expiring tax credits.

The budget office also estimates the bill will cut taxes by $3.7 trillion and cut spending by $1.2 trillion. The CBO has not yet completed an analysis of the macroeconomic effects of the bill.

The White House preemptively defended the bill just before the CBO release, with deputy chief of staff Stephen Miller accusing the nonpartisan office of being "lefty" and touting the legislation as a "dream bill."

After its release, White House Office of Management and Budget Director Russell Vought brushed off the CBO's estimate.

Vought instead claimed Trump's bill would reduct the deficit "when you adjust for CBO's one big gimmick -- not using a realistic current policy baseline." The White House maintains that the CBO has an "artificial baseline" that does not factor in the 2017 tax cuts.

House Majority Leader Steve Scalise slammed the CBO report at a press conference with Republican leadership on Wednesday morning, taking issue with it not recognizing potential economic growth, which it will do in a later, separate estimate.

"I get that we got to play by the rules of the referee, but the referee's been wrong. We've got a referee that tries to sack our quarterback a lot," Scalise said.

Separately, the CBO responded to Senate Democrats who had requested information on the effect of Trump's tariffs. That analysis found that while tariffs would cause the economy to shrink and add to inflation, they would reduce the deficit by $2.8 trillion.

The bill narrowly passed the House in May, but now some GOP members are signaling regret on their stamp of approval. Georgia Rep. Marjorie Taylor Greene, a staunch Trump ally, wrote in a social media post that she wasn't aware of a provision related to AI regulations and that she would have voted against the bill had she known it was included. Greene called for the measure to be removed by the Senate.

Later Wednesday, Trump is to meet with Senate Finance Committee members at the White House in his push to have the megabill passed by the Fourth of July.

The president has lashed out at GOP senators who are threatening to complicate its path forward, including Kentucky Sen. Rand Paul. Paul, who is specifically taking issue with the deficit, told ABC News following Trump's attacks that he's been "consistent" about his view from the start.

Sen. Ron Johnson, a Wisconsin Republican who sits on the Senate Finance Committee, has been critical of the bill the House passed to the Senate because it adds to the deficit.

"I refuse to accept $2 trillion-plus deficits as far as the eye can see as the new normal. We have to address that problem, and unfortunately this bill doesn't do so," Johnson said during an appearance on ABC News Live on Wednesday following the CBO release. The senator said regardless of individual CBO scores, the trajectory of deficits and debt is "hard to dispute."

Senate Minority Leader Chuck Schumer, the chamber's top Democrat, pointed to the CBO analysis as he railed against the Trump megabill in a press conference on Wednesday.

"The more you look at the bill, the worse it gets," Schumer said. He slammed the impact the changes to Medicaid are projected to have on people's health insurance as well as on rural hospitals and nursing homes.

"People will fall through the cracks and get phased out of coverage in the coming years. Death by 1,000 paper cuts. That's the intention of the Republican bill," he said.

ABC News' Michelle Stoddart contributed to this report.