Washington – Federal auditors determined the Senate plan to replace and repeal the Affordable Care Act would result in 22 million additional uninsured people by the year 2026.

That’s only slightly fewer uninsured than the House-approved health care bill, which the Congressional Budget Office said would result in an additional 23 million uninsured.

The Senate bill, called the Better Care Reconciliation Act, also would trim the deficit by $321 billion, about $200 billion more than the House-passed bill, mainly because the Senate is proposing deeper cuts in federal payments to Medicaid, the joint federal-state health program for the poor, the CBO said.

The federal auditors said under the bill, the number of uninsured would grow by 15 million next year, primarily because the penalty for not having insurance would be eliminated.

The increase in the number of uninsured would grow to 19 million in 2020 and 22 million in 2026.

In the later years, factors driving the higher uninsured rates include lower spending on Medicaid — likely to result in reduced eligibility for the program in many states – and the Senate bill’s smaller subsidies to help low- and medium-income individuals and families buy insurance

“The CBO and Joint Committee on Taxation expect that this legislation would increase the number of uninsured people substantially,” the agency’s report said. “The increase would be disproportionately larger among older people with lower income — particularly people between 50 and 64 years old with income of less than 200 percent of the federal poverty level.”

Democrats on Monday jumped on the CBO’s analysis that millions of Americans would lose their coverage under the Senate bill.

“CBO confirms this bill is a humanitarian catastrophe waiting to happen,” Sen. Chris Murphy tweeted. “My God, why would you choose to do this to your country?”

Rep. Elizabeth Esty, D-5th District, said, “This CBO report confirms the reality of the Senate GOP’s secret legislation. This bill is cruel. It will hurt Americans.”

Better news for Republicans is that the CBO also said the Senate bill would  help stabilize insurance markets and – after an increase in premiums in 2018 – the average cost of  health insurance would go down.

But the eventual decline in premiums would come because insurers would be able to offer skimpier plans, and federal subsidies would be based on a less comprehensive “bronze” plan and not the “silver” plan they are based upon now, the CBO said.

The CBO said market stabilizers include the Senate bill’s continuance of subsidies to purchase insurance “which would maintain sufficient demand for insurance by people with low health care expenditures.”

Other stabilizers include the continuation for two years of cost-sharing reduction payments which limit out-of-pocket costs to low- and moderate-income people and additional federal funding to states to help insurers bring down the cost of covering very sick people.

“That stability in most areas would occur even though the premium tax credits would be smaller in most cases than under current law and subsidies to reduce cost sharing — the amount that consumers are required to pay out of pocket when they use health care services — would be eliminated starting in 2020,” the CBO said.

The release of the analysis comes at a time when a number of GOP senators are weighing whether to support the bill.

Senate GOP leaders hope to hold a vote on the Better Care Reconciliation Act this week, before Congress breaks for its July 4^th recess.

But Democrats, including Sen. Richard Blumenthal, D-Conn., vow to use parliamentary procedures to introduce dozens of amendments to delay a Senate vote on the bill this week.

“We’re seeking to slow other committee meetings as well as the debate itself,” Blumenthal said at a press conference in Hartford on Monday. “There are a variety of tools we use. I can’t go into all the specifics now because we will be deciding on the strategy, literally, tonight and tomorrow, and I don’t want to prejudge what it will be. You can take it to the bank that we will use every tool available to slow and stop this runaway train.”

The bill was amended Monday to address the concerns of several GOP senators and the insurance industry that without the Affordable Care Act’s mandate to purchase insurance, people would “game” the system by holding back on purchasing insurance until they were sick.

The change would penalize those who let their insurance coverage lapse for more than 62 days by barring them from buying insurance for six months.

Other changes also are expected as Senate Majority Leader Mitch McConnell works to garner support for his bill. The GOP has a 52-48 majority in the Senate and can only afford to lose two votes, with Vice President Mike Pence as the tie-breaker.

Conservatives, including Sen. Ron Johnson, R-Wis., say the Senate bill is too much like the Affordable Care Act.

“Like Obamacare, it relies too heavily on government spending and ignores the role that the private sector can and should play,” Johnson said.

On the other hand, moderate Senate Republicans, and a number of Republican governors, are opposed to the bill’s cuts in the federal share of Medicaid.

On Monday, the American Medical Association came out against the bill, saying it  violated the precept of “doing no harm.”

“It seems highly likely that a combination of smaller subsidies resulting from lower benchmarks and the increased likelihood of waivers of important protections such as required benefits, actuarial value standards and out-of-pocket spending limits will expose low- and middle-income patients to higher costs and greater difficulty in affording care,” AMA CEO James Madara wrote in a letter to McConnell and Senate Minority Leader Chuck Schumer, D-N.Y.

America’s Health Insurance Plans, the trade association for the nation’s health insurers, has not announced a position on the bill, saying “the bill is evolving, and we’re analyzing.”

But AHIP spokeswoman Kristine Grow said “we remain very concerned about what it means for those who rely on Medicaid for coverage and care.”

Reporter Kyle Constable contributed to this story.