We already knew Congress could do a lot to roll back the administration's last-minute rules and regulations using the Congressional Review Act. Under a process that the Senate minority cannot filibuster, Congress can easily undo any regulations that have been published in the Federal Register in the last 60 legislative days. That means anything back through June 13.

Republicans in Congress have already announced their intention to roll back five relatively obscure rules, and several more high-profile ones are sure to follow. But on Thursday night, Kim Strassel came across something more interesting about how the CRA works. If she's right, this law is a lot more powerful than I thought, and apparently more powerful than most members of Congress thought as well.

For each rule, the CRA requires the federal agency making it to issue a report to Congress. And it turns out that the 60-day time limit for Congress to roll back that rule starts either when the rule is published or Congress receives the report on it — whichever comes later.

"There was always intended to be consequences if agencies didn't deliver these reports," [the Pacific Legal Foundation's Todd] Gaziano tells me. "And while some Obama agencies may have been better at sending reports, others, through incompetence or spite, likely didn't." Bottom line: There are rules for which there are no reports. And if the Trump administration were now to submit those reports—for rules implemented long ago—Congress would be free to vote the regulations down.

Assuming this is all accurate, it will be very interesting to see which older rules are now vulnerable due to such an oversight in issuing a report. The failure to cross T's and dot I's could be very costly for those portions of the liberal agenda that Obama sought to advance through the regulatory process.

As Strassel explains, when Congress undoes a federal rule under the CRA, the agency in question is forbidden to issue any rule "in substantially the same form" unless Congress passes a new law to authorize it. This means that if a rule is undone through this process, the next Democratic president who tries to restore it will probably be taken to court, and lose.

This seems too good to be true, so don't get your hopes up too high. The real question is going to be which rules never had a corresponding report submitted, and were thus carelessly left open to repeal under the CRA. Will they be important ones that go back to the beginning of Obama's administration?