Remember Irangate?

THERE'S SOMETHING PECULIAR about an obsession with the Iran-contra scandals of the mid-1980s. The tale has grabbed the public imagination only fitfully. Perhaps it was all just too complicated for our sound-bite culture. Ten years on, one wonders: who the heck was Manucher Ghorbanifar, anyway?

Of the few for whom Iran-contra remains meat and drink, none has been so obsessed as Lawrence E. Walsh, the distinguished lawyer who was appointed special prosecutor in December 1986. Yet when he gave up the chase more than six years later, even some of his staunchest supporters thought he had let things drag on and on. Walsh's new book, Firewall: The Iran-Contra Conspiracy and Cover-Up (544 pages. W.W. Norton. $29.95), tries to explain the investigation. His central argument is straightforward: in shipping arms to Iran and syphoning off some proceeds to fund the Nicaraguan contras, members of the Reagan administration broke the law. They then lied and delayed investigations in order to build a ""firewall'' around Ronald Reagan, who was himself implicated in the arms shipment in the vain hope of bargaining for the release of American hostages in Lebanon. Unfortunately, Walsh sheds little light on the great remaining mystery of Iran-contra: did Reagan know Iranian cash was being diverted to Nicaragua?

Most of Walsh's work concerned the cover-up of Reagan's involvement, which led to Walsh's indictment of for- mer defense secretary Caspar Weinberger for lying to investigators. But Weinberger had opposed the whole Iranian end of the scheme; to indict him six years after the fact smacked of overkill.

Walsh admits that ""criminal prosecution is a stiff and clumsy procedure, particularly in dealing with sophisticated, politically motivated conduct.'' That is true. There were crimes committed during Iran-contra, and few of the most egregious criminals paid for it. But not every policy disagreement, even if it involves the breaking of laws, is best pursued through the courts. To do so is to invite even more secrecy in government and stop good people volunteering for public service. And then we all lose.