MORE THAN 10 days have passed since Lester M. Crawford abruptly announced his resignation as commissioner of the Food and Drug Administration. At the time, he stated nothing more than that, at age 67, it was "time to step aside." Even by the low standards of phony resignation excuses, this one was unusually lame: Mr. Crawford had been confirmed as commissioner only two months previously, after holding the job of acting commissioner for a year and a half (and spending a good chunk of that time struggling to be confirmed). Speculation about the real reasons is rife: Mr. Crawford has denied an allegation of financial impropriety. The FDA refuses to say anything on the matter.

Certainly Mr. Crawford's brief term contained no shortage of political controversies. Among them was a promise he made to Sens. Hillary Rodham Clinton (D-N.Y.) and Patty Murray (D-Wash.) to make a decision about the emergency contraceptive Plan B, whose over-the-counter use is opposed by conservative groups but approved by the FDA's scientists. When he broke that promise within weeks of winning Senate confirmation, delaying approval further, the FDA's top women's health official resigned in protest, stating she could no longer work for an agency that politicized regulatory decisions that are supposed to be made on scientific and legal grounds. Was Mr. Crawford being punished for his promise to the two senators? Does that mean the FDA no longer has an independent, apolitical standing? If not -- if the issue really is corruption, or personal behavior, as some who know Mr. Crawford claim -- then to say so would help clarify the relationship between the agency and the White House.

Several members of Congress have called for an explanation of the resignation. But there should be no need for theatrics. A major public official has resigned; the administration owes the public an explanation. Without one, installing a permanent successor will be extraordinarily difficult: It is impossible to make a judgment about who should run the FDA until the administration's intentions toward the agency are better known. We have argued in the past that it is bad politics to leave this important agency leaderless. It is even worse to leave the FDA leaderless without explaining why.