FOUR HUNDRED THOUSAND more Virginians could get health-care coverage, quickly and at minimal cost to the state. All that’s needed is for anti-Obamacare dead-enders in the General Assembly finally to put the well-being of their people over partisanship, as Republicans in a variety of deep-red states now are doing.

Gov. Terry McAuliffe (D), not for the first (or 10th, or 50th) time, is making the argument for this totally reasonable expansion of health-care coverage to people who desperately need it. Some analysts suggest he knows he still can’t win in the legislature and is only teeing up the issue for the coming gubernatorial election. If so, that will be the fault of intransigent Richmond Republicans, whose position on the issue is now even less defensible than it used to be.

The Affordable Care Act extended the state-federal Medicaid program to cover a swath of low-income people, but the Supreme Court ruled that each state could decide whether to accept this expansion. Despite the fact that the federal government has offered to pay nearly the entire cost of covering newly eligible people, only 31 states and the District have taken the bargain. Because of GOP opposition in the General Assembly, Virginia has been one of the holdouts.

That, however, was before congressional Republicans failed to advance a repeal-and-replace bill. “We’re going to be living with Obamacare for the foreseeable future,” House Speaker Paul D. Ryan (R-Wis.) admitted last week, after pulling the bill from the floor .

The Medicaid expansion was only temporary, Republicans used to argue; Congress would repeal it or federal budget constraints would require rollback. So, the logic went, state leaders should not risk expanding Medicaid only to pull the rug out from under vulnerable people when congressional Republicans unraveled the program. This argument never made much sense: It is better to cover people for some time than none at all. With a swift repeal off the table, it is now thoroughly discredited. Indeed, more than ever, Medicaid looks like a sure bet. Protecting the program turned out to be a priority for moderate congressional Republicans in the House and Senate alike.

If the failure of the repeal-and-replace bill diminished Republicans’ policy case against expansion, it decimated their strategic rationale. Fighting Medicaid expansion across the country was a central part of the GOP plan to resist Obamacare, limiting the number of people who benefited from the law and therefore making it easier to tear up once Republicans took control of Washington. But the ACA proved too hard to eliminate anyway.

It is unsurprising that the week after the repeal-and-replace bill failed, the Kansas state legislature voted overwhelmingly to expand Medicaid in that ruby-red state. Kansas is unlikely to be the last place where GOP opposition softens as Republicans process the reality that Obamacare is the law of the land. The benefits are so clear, the costs to states are so low, the reasons to continue resisting are so insubstantial. It is time Richmond Republicans admitted as much.