Republican leaders on Capitol Hill were already looking at a messy political battle over the looming expiration of billions of dollars in Obamacare subsidies. Then the anti-abortion advocates showed up.

With a possible government shutdown less than a week away, Democrats’ big ask is that Republicans agree to extend the Affordable Care Act subsidies, which were expanded by Congress in 2021 and are set to sunset at the end of the year.

Insurance premiums are likely to skyrocket this fall without an extension, and some Republicans are open to cutting a deal, mindful that a failure to act could have dire consequences in the midterms.

But now prominent anti-abortion groups are wading into the debate, pounding the halls of Congress to make their case that the enhanced tax credits for ACA insurance premiums function as an indirect subsidy for services designed to end pregnancies. The argument could make conservative Republicans who already loathed the policy dig in further against greenlighting an extension.

It’s setting the stage for a major internal GOP power struggle that could pit hard-liners against moderates in more competitive districts, while also complicating the ability of Speaker Mike Johnson and Senate Majority Leader John Thune to allow a bipartisan deal to go through.

“It should be a huge factor for every Republican member,” said House Freedom Caucus member Eric Burlison (R-Mo.) of the pushback from anti-abortion groups. “Republicans have never voted for Obamacare, which is why it would be ridiculous for us to extend it.”

The lobbying campaign by anti-abortion advocates is exposing an internal GOP rift over health care that’s become a hallmark of President Donald Trump’s second term and could influence whether Republicans keep control of Washington. Over the summer, a conservative push to peel back Medicaid became a major flashpoint inside the GOP. Now similar camps are gearing up for battle over Obamacare subsidies and abortion, with Trump’s silence on the issue again proving to be a critical wildcard.

Yet Susan B. Anthony Pro-Life America, which mobilizes its large grassroots network to elect anti-abortion candidates, is plowing ahead, most recently making its case during a briefing last week with staffers for members of the conservative House Republican Study Committee.

Representatives from the organization are talking to the relevant congressional committees, lawmaker offices and party leaders “who are most engaged with finding a solution,” according to a spokesperson for the group. Marilyn Musgrave, the organization’s vice president of government affairs and a former Republican congresswoman from Colorado, has been meeting directly with lawmakers.

The in-person lobbying follows a letter to lawmakers in early September from nearly 90 anti-abortion groups, including Susan B. Anthony Pro-Life America, that called on Congress to “ensure that any extension of ACA subsidies is protected by the Hyde amendment,” adding, “the pro-life Congress must not be a party to the Obama policy of taxpayer funding for abortion.”

The Hyde amendment, named for the late Rep. Henry Hyde (R-Ill.), bars the use of federal funds to pay for abortion except in cases of rape or incest or when the mother’s life is at risk.

Democrats argue the ACA already has guardrails to ensure that the law complies with the Hyde amendment. They say the health law requires that insurance plans segregate premiums for abortion and non-abortion services into different accounts.

But opponents of abortion call that firewall a gimmick, arguing the tax credits effectively subsidize plans that cover abortion regardless of how the premiums are divvied up.

In a memo circulated by the office of Sen. Steve Daines this week, the Montana Republican similarly argued that “taxpayer funds are fungible” and that the enhanced credits make it easier for plans to offer abortion services.

“If Senate Democrats do not believe there are meaningful differences between the status quo and the Hyde Amendment, they should have no issues with codifying Hyde into law,” the memo reads.

Autumn Christensen, senior policy advisor at Susan B. Anthony Pro-Life America, said her organization was prepared to punish Republicans who vote for an extension without addressing this perceived discrepancy.

“Republicans have consistently stood against taxpayer-funded abortion in Obamacare, and we are confident they will continue to do so,” she said in a statement. “Extending subsidies without Hyde is a clear vote to expand abortion on demand, and every such vote will be scored by SBA Pro-Life America.”

Christensen and her colleague, federal affairs director Jamie Dangers, also distributed a memo at the Republican Study Committee briefing last week warning that extending the ACA subsidies “would be a betrayal of this summer’s victory” — a nod to Republicans’ sweeping tax and spending law that defunded Planned Parenthood.

Some Republicans are amenable to negotiation. For example, Sen. John Cornyn (R-Texas), who has said the credits should be extended before the midterms, suggested this wouldn’t be difficult to address. Cornyn is facing an intense Republican primary against Texas attorney general and Trump ally Ken Paxton.

“The Hyde amendment has been the rule since the mid-’70s or so, and so that will be something important for us to negotiate,” Cornyn said in an interview.

Thune, whose spokesperson did not return a request for comment, has left the door open to a possible deal while arguing that Democrats “created this problem” and should be the ones to initiate a proposal to address the subsidy cliff.

A group of Senate Republicans has been meeting to discuss legislation to extend the credits with new restrictions. Sen. Tommy Tuberville (R-Ala.), one of the members of the working group, said last week that Hyde protections were part of that discussion.

Johnson’s spokesperson also did not respond to a request for comment. But the speaker, who is firmly anti-abortion, has indicated his belief that Congress can easily wait until later this year to address the subsidies.

Rep. Brian Fitzpatrick (R-Pa.), who wants to secure an extension, doesn’t want to delay. He’s facilitating conversations with the leaders of the House Ways and Means Committee and trying to broker a bipartisan compromise with centrists in the Problem Solvers Caucus toward that end.

“I’m worried that there’s not enough focus being paid to it. We’re up against a real deadline. The rates are going to kick in probably Nov. 1, so we have October to get it done,” Fitzpatrick, a co-chair of the Problem Solvers Caucus, said in an interview.

Behind the scenes, however, Johnson’s leadership circle is aware of the dilemma and is increasingly viewing the abortion issue as deeply problematic for the prospects of a deal, according to three Republicans granted anonymity to describe private conversations.

Senior Republicans believe that leaders won’t be able to extend the subsidies without Democratic votes, and Democrats won’t support an extension that puts new restrictions on abortion coverage.

“You’re not going to be able to make progress on lowering Americans’ premiums if you start handing out right-wing trophies,” Sen. Ron Wyden, the top Democrat on the Senate Finance Committee, said in a statement. That panel, like Ways and Means, has jurisdiction over the tax credits.

Sen. Jeanne Shaheen (D-N.H.), who authored the legislation that created the enhanced credits, also intimated that bringing abortion into the debate would be a nonstarter for Democrats.

“We have to focus on good-faith solutions that can earn bipartisan support,” she said, adding that she has “always supported full access to women’s reproductive health services.”

Restrictions on abortion access won’t sit well either with all of the dozen House Republicans who have signed onto legislation that would extend the subsidies for one year, no strings attached. Many are moderates facing tough reelection fights next year, and any accolades they earn by extending the subsidies could be offset by the backlash from restricting reproductive health services.

Some of the Republican co-sponsors of the measure — including Fitzpatrick, Rep. Jen Kiggans of Virginia and Mike Lawler of New York — are also among the members who just wrapped up a fight with hard-liners over abortion and health care coverage in the GOP megabill that Trump signed into law in July.

And then there are those Republicans who don’t want any deal, for any reason, viewing the premium tax credits as bad policy regardless of the abortion issue. According to a Congressional Budget Office analysis published earlier this month, extending the credits for 10 years would cost around $350 billion and increase the number of people with health insurance by 3.8 million.

House Budget Chair Jodey Arrington (R-Texas) said the subsidies were “fiscally reckless” and “bad policy.”

“I don’t see a way to modify it,” he added. “It’s like putting lipstick on a pig.”