As the Republican party worked to undo the Affordable Care Act last summer, they kept running into a difficult reality: Voters strongly support the ACA’s consumer protections. These include the prohibition on insurers denying coverage to people with complicated health histories or charging higher premiums based on pre-existing conditions — pre-ACA problems that caused denials and unaffordable bills for women who gave birth, children with genetic conditions, and many others. Under the ACA’s requirements for guaranteed issue and community rating, many of those purchasing health plans on the individual market have insurance options that would previously have been out of reach. Many of them are starting to worry again, though, because the Trump administration has filed a legal brief that calls for an end to these consumer protections.

The issue has arisen because 20 states have filed a lawsuit claiming that the ACA is unconstitutional now that Congress has effectively eliminated the requirement for everyone to have health insurance. Their argument is that the 2012 Supreme Court decision found that the individual mandate was crucial to the law, so that in the mandate’s absence the law cannot remain. This doesn’t make sense, because the Court decision rests on a determination of what Congressional intent was, and in 2017, Congress clearly intended to eliminate the financial penalty for not having insurance while leaving the rest of the law intact. But, given that attempts to repeal the ACA have largely failed in Congress, it’s pretty much inevitable that its opponents will keep trying their luck in the courts.

The Department of Justice’s role is to defend legislation that has been passed by Congress and signed by the president, even if the president who signed it was from a different party. But the Trump administration has now filed a brief asking the judge in the case to void the law’s protections for people with pre-existing conditions. Former DOJ attorney Nicholas Bagley explains at the Incidental Economist what a tremendous break with normal procedure this represents:

Without question, then, there’s an argument to be made in the ACA’s defense. And the Justice Department has a durable, longstanding, bipartisan commitment to defending the law when non-frivolous arguments can be made in its defense. This brief puts that commitment to the torch.

I am at a loss for words to explain how big of a deal this is.

The laws that Congress passes and the Presidents signs are the laws of the land. They aren’t negotiable; they’re not up for further debate. If the Justice Department can just throw in the towel whenever a law is challenged in court, it can effectively pick and choose which laws should remain on the books. That’s as flagrant a violation of the President’s constitutional duty to take care that the laws are faithfully executed as you can imagine.

But don’t take my word for it. For Justice Department lawyers—I count myself among them (2007-10)—the duty to defend congressional statutes is at the core of what it means to be a government attorney. Yet, hours before the federal government filed its brief, three line attorneys from the Justice Department withdrew from the case. That’s almost unheard of. These are lawyers who have made arguments they personally disagreed with countless times. They’re civil servants. They’re good soldiers. Yet they could not sign it. That’s how far out the administration’s position is.

Do you want to live in a country where the Justice Department can embrace the craziest of arguments and decline to defend laws—or even enforce them!— on that basis? The President has a duty to take care that all the laws are executed, not just the ones he likes. And while there are cases in which the Justice Department has deviated from that principle, they are extremely rare.

Kaiser Family Foundation’s Larry Levitt explained to Talking Points Memo’s Alice Ollstein that even people with employer-sponsored insurance could be affected: If a person with a pre-existing condition was insured prior to joining an employer-sponsored plan, that plan could refuse to cover care for that condition. KFF researchers estimated that 27 percent of adults under 65 have health conditions that made them uninsurable under pre-ACA underwriting rules.

The Trump administration has already taken actions to destabilize the individual market (including halting cost-sharing reduction payments to insurers and drafting a rule to allow skimpy short-term plans) and make it easier for state Medicaid programs to stop covering enrollees who can’t get through all the paperwork hurdles to show that they’re working or having a reason why they can’t. Now we see that they’re also willing to flout a core tenet of our legal system — that the administration defends all the laws, not just the ones it likes — to undo one of President Obama’s signature achievements, and the peace of mind and financial stability it brought to millions.