Leaks are to Washington as cars are to Detroit. "Unauthorized disclosures" are the capital's chief commodity, and recently the city has had to cope with a surplus. Before the Senate Intelligence Committee managed to finish its probe of the Iran-contra affair last month, several versions of its report got into circulation prematurely. Minnesota's David Durenberger, the ranking Republican, even slipped the findings to Ronald Reagan; word of that indiscretion also leaked, provoking a minor uproar.
The new Senate Select Committee probing Iranscam is determined to avoid such unseemliness. To shield its investigation from political gossip as well as foreign intelligence services,...