As you may have heard, GOP Rep. Cathy McMorris Rodgers tried to celebrate Obamacare’s fifth anniversary by calling on constituents to share their horror stories about the law — whereupon many people responded by talking about how much the law has helped them. The story drew national attention.

Now McMorris Rodgers has responded to all the praise for the ACA by dismissing its significance: She now suggests people were only praising the parts of the law Republicans also support. But in the process, she has inadvertently demonstrated why Republicans should be hoping the King lawsuit against the ACA — currently the GOP’s best shot at doing the law serious damage — fails.

McMorris Rodgers, the Number Four in the House GOP leadership, is a very high profile opponent of the law. In 2014 she used her response to the State of the Union speech to draw attention to one “Bette in Spokane,” who, she said, endured a huge ACA-driven spike in premiums. The claim was seriously undermined when reporters looked at the actual facts of the situation.

McMorris Rodgers’ latest effort to rally Obamacare victims produced a bunch of stories from people who claimed the law had helped them get coverage they otherwise couldn’t. To be clear, it’s always dangerous to generalize either way about what anecdotal evidence tells us about a law’s performance. But McMorris Rodgers’ response to those voters is telling on its own terms.

Here’s what she told the Spokesman-Review:

McMorris Rodgers said Monday that many of the success stories seemed to be centered on reforms that both parties agreed on, rather than her concerns with the health care package.

“The stories are largely around pre-existing conditions and those that are getting health insurance up to age 26,” she said. “That’s broad, bipartisan support for those provisions.”

In other words, the coverage expansion that Obamacare has produced (and that people who responded to her are thankful for) is mainly due to the law’s protections for people with pre-existing conditions and for those up to 26 years old — and because those individual provisions have bipartisan support, they don’t really count as Obamacare! (The subsidies and Medicaid expansion played a large role in expanding coverage, but never mind that for now.)

It’s true that Republicans tend to support provisions like the protections for preexisting conditions; after all, they are very popular. But they can’t be tidily untangled from the law. The ACA’s protections for preexisting conditions rely on the individual mandate, because without it, people would simply wait until they got sick to sign up for insurance, driving up premiums; instead, the mandate broadens the risk pool. And the mandate requires the subsidies, so that lower-income people who’d face a penalty for remaining uninsured can afford to buy coverage.

Here’s where the King v. Burwell lawsuit comes in.

For years now, Republicans have played a clever game on the ACA. They keep calling for Obamacare repeal, while voicing support for the ACA’s most popular goals and claiming the secret GOP alternative would accomplish them without requiring the bad stuff (the mandates and tax hikes). But there is no GOP consensus behind any such alternative, probably because it’s really hard to reproduce the good things without the bad ones. Republicans fulminate for repeal, secure in the knowledge that it won’t actually happen and they’ll never actually have to produce that alternative.

But the King lawsuit threatens to upend that little arrangement. If subsidies are killed in three dozen states, that could cause untold numbers of healthier people to drop insurance. Yet the protections for people with preexisting conditions would remain, and they would be more likely to keep their insurance. Result: Premiums could soar, and the exchanges could ultimately collapse. In other words, if King succeeds, keeping the stuff that McMorris Rodgers and other Republicans say they like could drive prices way up.

If McMorris Rodgers and other Republicans actually want to keep those parts of Obamacare after a ruling striking down subsidies, then presumably they’d offer an alternative that does this. Indeed, the contingency plan floated by House Republicans does in fact promise to keep protections for preexisting conditions, while also vaguely vowing to maintain coverage for those who stand to lose subsidies, even as it would do away with the law’s “mandates.”

To be clear, it might be possible to accomplish these goals to some degree. But that would require Republicans to support federal spending to cover those who lost insurance. And without the mandate, it would probably require some other means of protecting people with preexisting conditions that would probably create weaker protections. But this alternative could then be compared to what Obamacare does. And if it falls well short, that will be clear.

The point is that, if King succeeds, it will force Republicans to either show an alternative that attempts to replicate the Obamacare goals that McMorris Rodgers herself says have bipartisan support — or reveal that they have no interest in coalescing behind something that does this on terms Republicans can accept. If Congressional Republicans did nothing, it’s certainly possible many would pay no political price for it. But at least their real stance on health care reform would finally be clear.