Republicans are already acknowledging they need to fix their gigantic tax law — but that could be impossible

The Republican tax bill officially became the law of the land on Monday, when most of its changes to the tax code went into effect. Though most Americans won't notice major changes until they file their 2018 taxes next year, some of the bill's effects will become clear in shorter order.

And as with any other law that significantly tweaks an existing system, this one is likely to require a series of technical fixes for any hiccups that pop up along the way.

"I can't imagine any major undertaking like this that doesn't require technical corrections in the future," GOP Rep. Kevin Brady, the chair of the House Ways and Means Committee who helped write the House version of the tax bill, told reporters last month.

But those fixes could be more difficult than Republicans expect. They will need cooperation from Democrats, who faced opposition when they wanted adjustments to the Affordable Care Act, the healthcare law better known as Obamacare. And this fraught political environment could complicate the tax law's implementation and future.