The astounding decision by the Trump administration to refuse to defend the Affordable Care Act against a spurious lawsuit by a bunch of conservative states has congressional Republicans in a pickle. The suit—and Trump’s position—would do what they’ve been promising their rabid base would happen for eight years: It would spell the end of Obamacare. The problem is: it would spell the end of Obamacare. Specifically, it would toss all the protections that more than one-quarter of the population with pre-existing conditions rely upon to continue their healthcare coverage.

The Trump administration has explicitly argued that those protections for people with pre-existing conditions should be struck down by the courts. Never mind that the legal argument is “pretty bad” in the summation of libertarian law professor Jonathan Adler, and “reflects poor understanding of severability doctrine, you see that in the state’s brief, and you see it implicitly in the DOJ brief insofar as they accept those arguments.” That means that the administration’s contention that because the individual mandate isn’t enforceable since the new tax law zeroed out the penalty, the rest of the law is unconstitutional is pretty much bullshit. Any court that hasn’t been completely taken over by Trump isn’t likely to advance the administration’s desire that these protections be declared unconstitutional.

But that doesn’t mean that the administration’s latest sabotage isn’t going to cause real harm in the meantime, while this case works its way through the courts. The statement from America’s Health Insurance Plans in response to the administration’s brief spells it out. The “renewed uncertainty in the individual market,” AHIP says, will “create a patchwork of requirements in the states, cause rates to go even higher for older Americans and sicker patients, and make it challenging to introduce products and rates for 2019.”

Back to congressional Republicans. When they were writing their so-called Obamacare replacement bill, they insisted that “Americans should never be denied coverage or charged more because of a pre-existing condition,” and that their legislation would “preserve vital patient protections, such as (1) prohibiting health insurers from denying coverage to patients based on pre-existing conditions, and (2) lifting lifetime caps on medical care.” Never mind that the legislation actually did undermine those protections, which is one of the reasons it ultimately failed in the Senate.

If they really meant it, that bit about protecting their constituents with pre-existing conditions, they should say so now. They should be filing briefs with the court in support of the law. They could pass another bill, making it crystal clear that these protections need to stand. They could stand up to Trump.

But they won’t. Which tells you everything you need to know about Trump’s GOP.