Those two measures encourage healthier people to leave the ACA exchanges, and either purchase the skimpy, but less expensive, short-term plans or forego insurance altogether. In a recent study, the Urban Institute projected about 9 million people would abandon the exchanges for one of those options. That would leave an older and sicker population remaining on the exchanges, which would raise premiums and reduce access to care, particularly for those who earn too much to qualify for the federal subsidies the ACA established.

But states have a surprising degree of autonomy to block Trump’s moves, and blue states are positioning themselves to do so. Five Democratic-leaning states in the Northeast already functionally prohibit the sale of short-term plans, and several others—Washington state has moved the quickest—may join them with regulatory or legislative limits.

Even more ambitiously, about a half-dozen states are examining ways to restore a mandate on individuals to buy insurance. The conversations are most advanced in Maryland, where state legislators are racing against an April 9 adjournment date to pass an individual mandate with an intriguing twist: The legislation would allow anyone without insurance to funnel their penalty into an account they could apply to buying coverage the next year.

As Maryland demonstrates, blue states are looking beyond blocking Trump’s moves and moving toward expanding the ACA framework. Several states are exploring proposals to restore a public option to compete with private insurers—a top liberal priority dropped from the ACA amid resistance from the insurance industry and centrist Democrats. Through the new proposals, Democrats would allow the uninsured to buy into state Medicaid plans. New Mexico legislators are examining the idea, and J.B. Pritzker, the front-runner for the Democratic gubernatorial nomination in Illinois, has endorsed it.

Not surprisingly, given its liberal lean and enthusiastic embrace of the ACA, California is pursuing multiple avenues to build on the health-care law. Anthony Wright, the executive director of the advocacy group Health Access California, told me his state is likely to pass legislation blocking short-term plans. And while many liberals in the state remain focused on the long-term goal of establishing a state-run single-payer system, where government directly pays for all health-care services, Wright expects growing consideration of restoring a mandate—coupled with financial assistance—and creating a Medicaid buy-in. With such steps, Wright said, California reformers believe they can reduce the state’s uninsured rate to “European [levels] of 1 or 2 percent … even without the single-payer options.”

That would place California on a strikingly different trajectory from red states, which are embracing the Trump rollback. With the Trump administration’s approval of Arkansas’s request earlier this week, three red states have now imposed work and reporting requirements that will limit access to Medicaid; the administration says 17 other states are considering similar ideas. Few red-state officials have raised objections to Trump’s moves to unravel the ACA’s mechanisms to share risk.