This is the year that agencies will be finalizing the rules that tell us what ObamaCare will look like. Funnily enough, the IRS is one of the most important agencies, because they decide how the penalties . . . er, pardon me, Justice Roberts, the taxes . . . get applied.

I wrote earlier this week about the rules governing adjunct professors, who thanks to an IRS ruling, are likely to qualify as full-time employees for the purposes of assessing penalties against universities. In response, universities--the most left-wing employers in the country, except for maybe labor unions--are already planning cutbacks in their adjunct hours.

If the universities are doing it, you know it must be coming in other sectors; anecdotally, workers in the retail sector are about to get hammered. Employers are going to be hypervigilant about making sure that employees don't get anywhere near the 30 hour threshhold. And for employers that use variable shifts, like restaurants (where slow nights see workers sent home early, and very busy nights see them staying hours late) that's going to mean scheduling a lot fewer shifts per worker.

But the IRS is wiley. They understand that this is the likely outcome of penalizing employers who do not cover 95% of their full-time-employees (defined as anyone working more than 30 hours a week). And just as they have written rules making it very difficult to, say, pay your salary to a corporation that pays you nothing, but owns a very attractive house and grocery stash that you are free to use, they are writing rules to make this sort of arbitrage difficult. Such as declaring that if you try to put people on part time so that you have fewer than 50 full time workers (the threshhold at which the penalty is triggered), they will add up the hours of your part time employees, and count two employees working 20 hours each as one full-time employee.

Welcome to the regulatory cascade. You write a rule, and people try to dodge it. So you write another rule, and they come up with a way to dodge that, so still another rule is needed . . . eventually you are penalizing things very far from the behavior you are trying to regulate. Think of the folks who want to make Sudafed a prescription drug in order to prevent meth labs from getting a hold of the stuff. Or functionally criminalize the carrying of large amounts of cash.

Undoubtedly, we can look forward to just such a cascade regarding part time employees. If the shifting is as broad as early reports suggest, there is going to be considerable pressure on the administration to crack down on it, perhaps by broadening the definition of a full time worker. That will trigger strategic responses from employers, and further rounds of crackdowns from the IRS.

Meanwhile, I don't know what happens to the employees, who are the mouse in this cat-and-mouse game. As I've noted before, the modern use of scheduling software--so that workers never know more than a week ahead what hours they'll get--is going to make that extra-hard on workers, because the variable shifts make it hard to tack on an extra part-time job. I'm not sure how some lower-end retail workers are going to survive the cutback. (Waitstaff, whose hourly wages are a fairly trivial part of their compensation, will presumably just clock out and keep working.) On the bright side, they will qualify for Medicaid.

Can the IRS prevent this? I don't know. The agency has very broad powers, and it's remarkably successful at keeping people from, say, shielding all their assets in a corporation. But can the agency simply demand that employers use mostly full time employees? That's pretty broad, even for the IRS--which just highlights how sweeping a change Obamacare really was.