Less than two weeks after the unveiling of the GOP Obamacare replacement, the party is already staring into the abyss.

The bill has had the worst rollout of any major piece of legislation in memory, and failure is very much an option. If the proposal falters, it will be a political debacle that could poison President Donald Trump’s relationship with Congress for the duration.

That relationship is awkward and tenuous. It is an uneasy accommodation between a GOP Congress that would find a more natural partner in a President Rubio, Cruz or Bush, and a President Trump who would, presumably, be happier to work with Speaker Dave Brat — the populist congressman from Virginia — than with Speaker Paul Ryan.

This is a product of how the Republican sweep of 2016 was won on separate tracks. Trump tore up many Republican orthodoxies and found a different way to unlock the electoral map. Congressional Republicans more or less stuck with the usual script.

As a result, there is no significant Trumpist wing in Congress. And there was no off-the-shelf Trump legislation that Congress could begin on immediately. In the campaign, Trump identified a constituency and a message, but the agenda often was symbolic (Mexico will pay for the wall) or nebulous (negotiating better trade deals).

The natural reflex, then, was to defer to the Republican leadership in Congress. Trump could have led with one of his distinctive proposals, the $1 trillion infrastructure plan, and wooed Democrats to support it and dared Republicans to oppose it. Instead, infrastructure has been put off to the second year, the polite way of saying it may not happen at all.

The congressional priorities are Obamacare repeal and tax reform, both of which could have been the first-year agenda items of the aforementioned hypothetical President Bush, Rubio or Cruz. It is true that Trump promised to deliver on both, but neither was part of his core message or won over marginal Trump voters.

For now, it is in the interest of both Congress and Trump to make their shotgun marriage work. If the health bill falters in the House, though, it will be the most fraught moment of GOP tension since the release of the “Access Hollywood” tape. Except the question won’t be whether congressmen and senators dump Trump, but whether Trump dumps them.

Even more than most politicians, Trump has no interest in owning failure. The explanation of the president and his supporters won’t be that he backed a flawed strategy and bill in the House and paid the price. It will be that he was stabbed in the back. He went along with a GOP establishment politics that doesn’t understand or care about Trump voters, and he can never make that mistake again.

There’s almost no question that Trump would win any blame game. He would have the larger megaphone, and much sharper elbows. He could instantly define Paul Ryan as a creature of the Washington swamp and decide to triangulate away from the GOP Congress rather than work with it.

This would mean Trump would be a president not without a party necessarily, but without a Congress. It would make major legislative accomplishments impossible, although if Obamacare repeal-and-replace fails, that might be the reality regardless.

Some skeptics of the Ryan bill hope that its defeat will allow the party to quickly move on to tax reform. But tax legislation won’t be any easier. It, too, is highly complex and will disappoint populists when it emerges that the Republican template for reform doesn’t take much account of the interests of working-class voters.

It is better for everyone that Obamacare repeal-and-replace succeed. Ryan should amend his bill to, among other things, get the coverage numbers up and make it a sturdier vehicle for the turbulence ahead. The alternative is a defeat that may precipitate a nasty, perhaps enduring, split in a party desperate to paper over its divisions.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.