Obamacare repeal has failed again, almost certainly for the final time. Seven years of Republican promises to uproot the thing and mulch the stump have ended in rejection by a Senate with a Republican majority. It’s hard to recall when last a political party inflicted such a defeat upon itself. Obamacare repeal was not one policy idea among many for Republicans, akin to the cap-and-trade plans that fizzled in the Democratic Congress of 2009-2010. It was the core commitment of the party, the indispensable preliminary to everything else Republicans wanted to do, from entitlement reform to tax cuts.

And then, with all the necessary votes in hand, facing no effective opposition in Congress, the thing just … collapsed, like a person tripping over his own feet while walking across an empty ballroom.

What went wrong?

President Trump’s Twitter feed blames weak-willed senators. Many outside observers blame the president’s own failures of leadership. Trump did nothing to mobilize public opinion, little to build consensus in Congress. He delegated almost all the work to congressional leaders, limiting his own interventions to occasional empty threats against stand-out senators like Alaska’s Lisa Murkowski.

But these explanations and many more like them look in the wrong place. Presidential leadership failed, yes, but the failure was not a failure of persuasion or a failure of negotiation. Lyndon Johnson himself could not have made a deal to move such unpopular legislation through Congress; Ronald Reagan could not have sold the largest Medicaid cut in history to the voting public. The failure was not tactical at all. The failure was vastly more fundamental than that—and the relevant failure of presidential leadership was the failure to acknowledge or redress the fundamentals.

The Republican Party had marched itself into a hopeless dead-end on health care. The party had promised not only to repeal the Affordable Care Act, but to replace it with something that would offer better coverage at a lower price—while also spending less public money and cutting the taxes that financed the whole thing. This was clearly impossible. Yet nobody dared say what everybody knew.

Only presidential leadership could have marched the party back out of this cul-de-sac. Theoretically, Donald Trump could have been the president to do so too. Of all the 2016 candidates, he had been the least beholden to outdated party ideology. He owed little or nothing to the interest groups that four years previous had compelled Mitt Romney to disavow his own health-care plan in Massachusetts. He was perfectly positioned to tell his own party: 2012 was the repeal election. We lost. Now it’s time to try something new.

Rescuing a party from unworkable commitments is a job only a presidential nominee can do.

It was Dwight Eisenhower’s nomination in 1952 that finished off Republican opposition to a permanent NATO commitment.

John F. Kennedy’s nomination served notice that the Democrats would end their long equivocation between pro- and anti-civil-rights wings.

Ronald Reagan put an end to the GOP’s long ambivalence about Social Security; Bill Clinton in 1992 reinvented the Democrats as a party that accepted limits to the growth of government.

It could have been Trump who likewise rescued the GOP from the excesses of Tea Party Republicanism. Many Trump supporters looked to him for just such a rescue during the primaries. Chris Ruddy, CEO of the populist conservative NewsMax and a close friend of Donald Trump’s, warned him in a shrewd March 2017 op-ed to steer clear of Paul Ryan’s austere health ideas.

Remember that Obama and Trump agreed on the key, positive premise that every American should have access to medical care.

But both Obamacare and the new GOP plan (let's call it Ryan Plan II), have a serious flaw: an onerous demand that almost every American should buy health insurance from the private market.

This demand, done mainly to please the insurance industry, has made the cure of simply expanding the less expensive Medicaid program a nonstarter.

Instead—and against Trump's own instincts and preferences, Trump ratified and recommitted his party to the most unpopular Tea Party excess of them all. Despite public opinion, despite his own beliefs, Trump failed because he could not say “no” to the party forces he had bested and beaten in 2015 and 2016. As Trump might put it: Weak! Sad!