Watch Rand Paul to understand why Obamacare repeal is in so much trouble.

Paul faces a more agonizing dilemma than almost any other Republican senator. A libertarian ideologue and Tea Party stalwart, Paul has spoken vociferously about the imperative of repeal for years.

Yet Paul also represents a state that has done well out of the Affordable Care Act. Four hundred and forty thousand Kentuckians have gained coverage under the ACA; Kentucky’s uninsured rate tumbled from 20 percent in 2013 to 7.5 percent in 2015.

Even more strikingly, it is Kentucky’s Appalachian Southeast that has seen the biggest gains from the ACA. And it so happens that southeastern Kentucky voted more staunchly for Paul’s 2016 reelection than did any other section of the state.

Paul won 76.6 percent of the vote in Clay County, where 15.6 percent of the total population has gained coverage via the ACA’s Medicaid expansion. He won 81.5 percent of the vote in Jackson County, where 15.1 percent owe their Medicaid to the ACA. He won 84 percent in Leslie County, where 18 percent would lose Medicaid if Obamacare were repealed.

Very understandably, the version of Obamacare repeal that Senator Paul introduced in January 2017 leaves Medicaid untouched. But, of course, Paul has no such assurance about the version of reform being incubated by the House Republicans under Speaker Paul Ryan. Which may explain why Paul has emerged as the most outspoken Republican critic of Ryan’s health-care approach.

According to Paul himself, his resistance to the Ryan approach is driven by his own superior ideological purity. “I think it is Obamacare Lite. I didn’t sign on to vote for a new government program,” Paul told Fox News last week. Yet Paul must appreciate the practical consequences of his super-purist objection. The Ryan repeal plan is simultaneously under fire in the Senate from lawmakers who fear it goes too far. Senators Susan Collins and Bill Cassidy have introduced a measure that would preserve the ACA in its present form for those states that wish to participate—presumably including Cassidy’s state of Louisiana, which has signed up for the ACA’s Medicaid expansion.* ACA repeal can only happen if it is supported by all Republicans, accommodationists and purists alike. The vote tally won’t care why a Republican defects from the Ryan bill—only that he or she does.

Paul’s demand—repeal the ACA and replace it at the same time, even the same day—is obviously unworkable, even aside from the need to rally sufficient votes in the Senate to overcome a Democratic filibuster. You have to imagine that he and other self-imagined purists appreciate that.

But what is workable is a more familiar play: to strike a heroic attitude of principle while in fact supporting as the least-bad option a law that you nominally oppose. Bob Dole famously advised that the safest position for a politician is to “support the bill that failed; oppose the bill that passed.” One doubts that Rand Paul will be the only Republican to recognize the advantages of denounce-and-preserve over repeal-and-replace.