Giddy over controlling both ends of Pennsylvania Avenue for the first time in a decade, Republicans have set themselves a lofty goal: to unravel the legacy of Barack Obama. Health care, trade pacts, environment regulation, financial oversight––you name the policy area, the GOP is set to roll it back.   

Washington being Washington, even the grandest projects tend to rely on complex, mind-numbingly arcane mechanisms to get the job done. (This is how lawmakers do what they do: bore and/or confuse the public into ignoring what they’re up to until it’s too late.) Dismantling a presidential legacy is no different. Thus, for the past couple of months, conservatives both on and off Capitol Hill have been noodling over the most effective, efficient means of wiping out as much of the 44th president’s work as possible.

To this end, one obscure legislative tool is suddenly getting scads of attention: a rarely used oversight measure called the Congressional Review Act, or CRA. Passed in 1996 as part of Newt Gingrich and the Revolution’s “Contract with America,” the CRA allows Congress to overturn rules freshly issued by federal agencies without going through all the rigamarole required to pass regular bills. Most notably, CRA resolutions cannot be filibustered, meaning Republicans need only a simple majority in both chambers to get the rollback party started. Those last-minute “midnight regulations” Obama has been so defiantly issuing on everything from fuel efficiency standards to the funding of Planned Parenthood? Any—or all––could easily be rendered Dead On Arrival under the CRA.

More alluring still for lawmakers, once a rule has been axed via CRA, agencies are barred from issuing a similar rule without express authorization from Congress. So not only is the CRA route quicker and easier than the usual legislative slog, it provides insurance against a pesky replacement rule.

You might assume a law with such potential impact would have been tough to pass, or at least have been the source of hot partisan squabbling. Quite the opposite: If there’s one thing legislators from both teams agree on, it’s that they deserve greater authority vis-à-vis the uppity executive branch. And so the CRA passed quietly as a rider to the Small Business Regulatory Enforcement and Fairness Act, aka SBREFA. (Remember: Keep it complicated, dull, and, ideally, heavy on impenetrable acronyms.)

At the time, it enjoyed solid bipartisan backing. Democratic Senator Harry Reid issued a joint statement, with Republican colleagues Don Nickles and Ted Stevens, praising the act for helping “redress the balance” between the branches. Democratic Senator Carl Levin cheered, “If a rule goes too far afield from the intent of Congress in passing the statute in the first place, we can stop it. That’s a new day, and one a long time in coming.”

No question CRA made rollback simpler: Under the CRA, every rule issued by an agency must be submitted to both chambers for review. Once notification occurs, any lawmaker can file a “resolution of disapproval” of the rule within 60 legislative days. (Not to be confused with calendar days!) With all Congress’s comings and going, the exact deadline can be tough to calculate (the House and Senate parliamentarians are the official arbiters), but the Congressional Research Service estimates that the new congress can go after rules issued as far back as mid-June of last year.

Using special CRA procedures (the eye-glazing details of which I will skip, but which can be found here for the masochists among you) a resolution can be fast-tracked through committee and onto the floor of the Senate, where it is limited to 10 hours of debate. (The act does not provide similar fast-tracking in the House because, why bother? No filibusters.) Once simple majorities in both chambers vote their support, the resolution is then whisked over to the president’s desk for consideration. Easy-peasy.

Now, it doesn’t take a political genius to spot the sticking point here. Under normal circumstances, what self-respecting president is going to sign a resolution overturning a rule issued by his own administration? Answer: none. Which explains why, in 20 years on the books, the CRA has been successfully used exactly once. That was in early 2001, when a Republican congress sent its new Republican president (Bush 43) a resolution targeting a workplace-ergonomics rule issued in the closing days of the Clinton administration. (Bush signed it, and no similar rule has been attempted since.)

To be sure, Congress now and again has some fun with the CRA. During Obama’s tenure, for instance, congressional Republicans passed a handful of symbolic resolutions targeting rules issued by the Obama administration. The president, of course, vetoed them all.

And therein lies the often fatal flaw of the CRA. The threat of presidential veto renders it a hollow threat. Except. It works like a charm under very specific political conditions: namely, during a presidential transition period in which Congress is held by the same party as the incoming president and so has a shared interest in undoing the work of the outgoing president of the opposing party.

Basically, the exact conditions that will exist come January 21.

Unsurprisingly, Republicans have been invoking the CRA with great fondness of late. In a November chat with home-state reporters, Texas Republican Senator John Cornyn predicted “a lot of action” involving the act in the coming months. The Senate Republican Policy Committee has identified several of its top candidates for rollback, including rules on federal land use, school accountability measures, and Planned Parenthood funding. Shortly before Christmas, the conservative Heritage foundation issued a briefing, merrily titled “Stars Align for the Congressional Review Act,” urging Congress to “make the CRA a frequently used weapon in the fight against red tape.”  

GOP lawmakers indeed look forward to exploiting this rare alignment. Folks on the Hill estimate that CRA will be used to nix somewhere between 8 and 12 rules. (Which ones should get the axe, and in what order, remains a subject of energetic internal debate. Those mentioned to me include the Fair Pay and Safe Workplaces executive order, greenhouse-gas emissions standards for heavy-duty trucks, and the Stream Protection Rule.) Not that there aren’t plenty of others they consider worthy of takedown. It’s largely a question of floor time, they tell me. The incoming president has his own priorities, not to mention a raft of appointees to be confirmed. Even with fast-tracking, lawmakers can invest only so much time tackling individual rules.  

There is, in fact, a push in the House to supercharge the CRA. Currently, only one rule can be tackled per resolution. The Midnight Rules Relief Act would change that, allowing Congress to bundle and dispatch multiple rules with a single resolution, making the process even easy-peasier. The House passed the bill (for the second time since Election Day) on Wednesday, its second day back from break. Obama has vowed to veto it, but that only matters for another couple of weeks.

Safe to say, Democrats will find themselves less than delighted by CRA’s impact on the “new day coming” later this month. Fiddling with the legislative process invariably has unforeseen consequences. And now congressional Dems have little recourse but to try and gum up the works as much as possible, using whatever obscure, complex mind-numbingly arcane tools they can dig up. It won’t be pretty—but, then again, so little of what Congress does ever is.