After pitching himself to voters as a hard-nosed negotiator who could easily wring out of the political system accomplishments that had eluded all past presidents, Donald Trump turns out to be uniquely bad at quarterbacking legislation through Congress.

Perhaps because Trump lacks both the ideological commitment and attention span that steady-handed leadership requires, the Republicans who run Congress have eyed a large, temporary, regressive tax cut as consolation—the same contingency they adopted in the early months of the George W. Bush administration. The party might stumble over health care and government funding, but if there’s anything Republicans should know how to do blindfolded it’s cut tax rates on a partisan basis.

Trump is now doing everything in his power to prove that assumption wrong.

“President Donald Trump has ordered White House aides to draft a tax plan that slashes the corporate tax rate to 15%,” the Wall Street Journal reported on Monday, “even if that means a loss of revenue and exacerbating the procedural and partisan hurdles he faces in search of his first major legislative victory, according to people familiar with the directive.”

At a glance, Republicans must have been thrilled to learn that Trump is now backing a massive, deficit-increasing corporate tax rate cut. But in his haste to rush a blueprint out the door ahead of his 100th day in office this Saturday, Trump committed his administration to a plan that very likely won’t work, even if Republicans in Congress support it unanimously.