WASHINGTON — The polarizing politics of abortion have burst into the congressional budget debate, overwhelming bipartisan efforts to help millions of consumers who buy their own health insurance policies get relief from soaring premiums.

On Monday, Senate and House Republicans released their latest plan to stabilize the Affordable Care Act’s insurance markets.

It calls for new federal money to offset the cost of treating the sickest patients and restores insurer subsidies that President Trump terminated last year.

That’s clearly a shift from when repealing “Obamacare” was the Republicans’ demand. But the fine print of the offer includes restrictions on abortion funding that Democrats have already rejected, a “poison pill” to abortion rights supporters. They say the proposal could block abortion coverage by some health insurance plans consumers purchase with their own money.

Lawmakers of both parties have been negotiating over a health insurance stabilization bill for months, but chances it will be added to the budget deal appear to be dwindling. Some experts estimate such legislation could reduce premiums by 20 percent to 40 percent, after two years of relentless increases.

The office of one of the leading Democratic negotiators, Sen. Patty Murray of Washington, on Monday called the Republican offer “partisan,” saying in a statement it came as a surprise.

In an interview Friday, Murray said her Republican counterparts have only recently started raising the issue of abortion restrictions.

“To me that is just unacceptable,” Murray said. “Why would they add it on at the last minute?”

She complained that some Republicans were taking the stabilization bill “hostage.”

Republicans say their longstanding support for restrictions on abortion funding is well-known.

Abortion is just one of several divisive social issues complicating prospects for a $1.3 trillion spending bill that would keep the government open and provide funding increases for military and domestic programs.

Others include a Republican demand for stronger “conscience” protections for clinicians, and a Democratic maneuver to protect family planning money for Planned Parenthood clinics.