Sen. Dianne Feinstein issued a stinging rebuke Friday to the push by congressional Republicans to repeal and replace Obamacare, condemning her GOP colleagues for advancing a health care bill she said was written in private “by 13 white men.”

“Understand that this is real, that it’s happening now, and that we must stop it,” Feinstein said at a news conference at the University of California, San Francisco, Benioff Children’s Hospital. “It must be defeated.”

The proposal would strip 22 million Americans of health coverage by 2026, according to an analysis from the nonpartisan Congressional Budget Office.

State health officials say it remains unclear how many Californians could potentially lose health coverage because the bill is still under negotiation, but early estimates show it could be as many as 5 million.

California would see the biggest increase in the number of uninsured, according to state health insurance regulators. Up to 4 million people enrolled in Medi-Cal could lose coverage. More than 1 million people enrolled in the Covered California exchange could see soaring premiums and other out-of-pocket costs, or risk losing health coverage altogether.

Feinstein criticized senators for political maneuvering, and called on opponents to urge Senate Republicans to vote against the bill.

“What the Republicans have done, essentially, is said, ‘OK, we’ll pass the bill now, but these cuts won’t go into effect for a couple of years.’ So it’s a little tricky — you get past the next election without a cut,” she said. “There is no Democrat in the United States Senate that will vote for this bill – it will be 51 Republicans or nothing.”

She pointed out that Senate Majority Leader Mitch McConnell has not yet brought the bill to the Senate floor for a vote.

“My sense is that he won’t until he has the votes, and my sense is that he’s not going to have the votes,” Feinstein said. “I think we’re very close to defeating it.”

The Republican bill, backed by President Donald Trump, would gradually shift health care costs covering low-income people from the federal government to states. For California, those federal cuts that currently fund Medi-Cal would amount to more than $30 billion per year over the next decade, according to the state Department of Health Care Services.

By 2037, California would lose $114 billion in federal funding for Medi-Cal under the Senate GOP bill.

“Our biggest concern is that it’s already a marginally funded program,” said Mark Laret, president and CEO of UCSF Health. “If cuts come, there will be less payments for doctors and hospitals, therefore fewer doctors and hospitals to administer care ... and less access to care.”

Supporters of the bill note that the CBO has found its huge tax cuts will reduce federal revenue by some $700 billion, but that savings from program cuts will still allow a federal deficit reduction of more than $320 billion over the next decade. Most of the savings would come from federal cuts to Medicaid, or Medi-Cal in California.