In one of their first acts in the majority, House Democrats asked the federal courts to let them intervene to defend the Affordable Care Act from the ongoing legal challenge being brought by Republican states.

Democratic leaders, after an approving vote on the House floor on Thursday, filed their motion Friday with the US district court in Texas that’s considering the case. Their attorneys asked that the House be permitted to “exercise its right to intervene ... so that it may defend the validity of the ACA.”

They cited a long list of federal statutes and case precedents to justify the motion. The Democratic brief noted that the Justice Department, which would usually be tasked with defending a federal law from a legal challenge, has instead decided to join the Republican-led states in arguing that Obamacare’s individual mandate and other key provisions in the law are now unconstitutional.

“While the Department of Justice normally defends the validity of Acts of Congress when they are challenged in court, here it has joined the plaintiffs in attacking the validity of the individual mandate,” the motion reads. “The House has a unique institutional interest in participating in this litigation to defend the ACA against the remaining challenges, and intervention should be granted.”

Twenty Republican states brought the lawsuit arguing that since the ACA’s individual mandate penalty was repealed in the Republican tax bill, the entire law is now invalid; they leaned on the logic in Chief Justice John Roberts’s decision in the 2012 case challenging the law, in which Roberts found the mandate was justifiable as a tax, to make their case.

They’ve been joined in part by President Donald Trump’s Justice Department, which argued the mandate and the law’s provisions protecting people with preexisting conditions must be overturned — but not the rest of the law. Medicaid expansion, for example, would remain.

Federal Judge Reed O’Connor agreed with the states in December and ruled Obamacare should be overturned entirely. However, his decision has been put on hold (allowing the law to stay in place for now) while Democratic-led states appeal the ruling to a higher court.

The mechanics here are a little wonky. O’Connor has, technically, only ruled on one question of several that the Republican states brought in their litigation. House Democrats have therefore asked the judge to allow them to intervene on the remaining counts that are still unresolved. They will, simultaneously, ask the appeals court to let them join the appeal being brought by Democratic states that seeks to reverse O’Connor’s decision to invalidate all of the ACA.

Legal experts — who are generally dismissive of the lawsuit, on the basis that if Congress wanted to overturn the rest of Obamacare when they repealed the mandate penalty, they would have — believe the first count, already ruled on and appealed, is the most important. So in a certain sense, the House motion on Friday is symbolic.

The bigger question is whether they are given standing to participate in the Democratic states’ appeal of O’Connor’s ruling. House attorneys said they would seek to intervene in that case as soon as they are able; there is not yet a case number for the appeal.

But the point is clear: House Democrats, fresh off winning an election where health care was a major issue, want to be allowed to stand in court and defend Obamacare. They are now taking the necessary legal steps to do so.