In any major piece of legislation, flaws are practically inevitable, and even careful policymakers often don’t notice the errors until a new law takes effect. With this in mind, perhaps it’s unsurprising that the Republicans’ regressive new tax plan is riddled with dozens of mistakes.

In this case, however, the details matter. While some errors are probably unavoidable, GOP lawmakers were unusually careless in throwing together their reckless tax breaks for the wealthy, effectively scribbling the legislative text on the back of envelopes filled with campaign contributions.

Asked to describe the scope of the mistakes in the Republican tax law, Marty Sullivan, chief economist at the non-partisan Tax Analysts, told Politico, “This is not normal. There’s always this kind of stuff, but the order of magnitude is entirely different.”

Fixing these mistakes will require congressional action, and wouldn’t you know it, the Democrats who were locked out of the process last fall don’t seem especially eager to cooperate now. The Washington Post reported over the weekend:

Republicans aiming to use an upcoming spending bill to fix a glaring problem with their recently passed tax overhaul are running into a wall with Democrats, who were shut out of the tax law process and now don’t want to cooperate unless they get something in return. […] Democrats aren’t willing to go along so easily. They say they warned Republicans that pushing through the law in a matter of weeks – without public hearings – would result in problems and unintended consequences. And now that such issues are emerging, some Democrats resent being asked to lend their votes to a solution.

That’s not the funny part. Rather, what’s truly amazing is the Republicans’ incredulity.

Axios had a great report on this yesterday, noting that after the Affordable Care Act became law, and officials found technical glitches, Republicans refused to consider even the modest fixes. Now, many of those same GOP lawmakers seem astonished that Democrats are returning the favor.

“Surely Democrats have to understand that when you make a mistake like that, it ought to be fixed without bargaining with them on something else,” Sen. Chuck Grassley (R-Iowa) said.

As best as I can tell, he wasn’t kidding.

Look, the comparison isn’t even altogether fair to Democrats. When the health care law was considered, it went through a lengthy process featuring hearings, meeting, forums, and debates. Republicans weren’t just invited to participate in the policymaking process, Democrats actually incorporated several dozen GOP amendments into the law itself.

When Republicans then refused to consider technical fixes, the GOP was simply being spiteful, trying to undermine the federal law, on purpose, in the hopes that the system would be less effective for the public.

Republicans who blocked Democrats from having any role whatsoever in shaping the new tax law, meanwhile, are suddenly appalled by Dems’ reluctance to simply go along with GOP-proposed fixes.

Sen. John Thune (R-S.D.) said, “Most of the ACA stuff, we kind of wanted to undo the whole thing. This is a technical, unintended consequence that has broad ramifications for both Democrats and Republicans.”

Yes, and there were technical, unintended consequences in the health care law that had broad ramifications for both Democrats and Republicans – and John Thune nevertheless rejected any effort to correct those errors.

It’s as if GOP lawmakers believe there should be two entirely different governing standards for the parties: a harder one for Democrats, an easier one for Republicans.

For Dems to go along with this would be folly.