A Fourth Year of Law School?

Cardozo Law Professor Edward Zelinsky is taking some well-deserved ribbing for his suggestion that law school should be expanded to a four year program. Critics of his piece have noted the tension between his argument that law school should be longer and should be more affordable,

The most serious argument against a fourth year of law school is the additional cost it would entail. Legal education is already too expensive. Adding a fourth year would impart even greater urgency to task of controlling the expense of law school, just as there is currently great urgency to the task of controlling the costs of undergraduate education.

As if it makes sense to increase the cost and duration of law school by a third, and only then address the urgent need to make law school more affordable. But I also take issue with this claim,

An ancillary benefit of a fourth year of legal education would, in the short run, be a reduction in the supply of law school graduates.

Let's say that starting in 2014, every new law school student were enrolled in a four-year program instead of a three-year program. In 2017, very few law school students would graduate. In 2018, assuming prospective law school students didn't turn away from the additional burden in droves, the market would return to "business as usual". So there would be a whopping single year in which a shortage of law school graduates would significantly affect the legal job market, which may help lawyers you graduated a year, perhaps two years before, but would be of little help to anybody who graduated earlier and of no help to anybody who graduates later. Still, not to damn his point with faint praise, it's not the weakest of his arguments.