Outing outrage

As the letter noted, the destruction of Plame's cover, through a leak to columnist Robert Novak, "damaged US national security, specifically the effectiveness of US intelligence-gathering using human sources." For this reason, signers of the letter called the outing of Plame "an unprecedented and shameful event in American history."

This act -- by sources Novak described as senior administration officials -- struck at the CIA functions that are most needed for President Bush's war on terrorism. So the president's response should not be limited to lamenting that the sources of such leaks are rarely discovered and turning the matter over to a Justice Department investigation.

Even if US Attorney Patrick Fitzgerald -- who was brought in as a respected outside prosecutor to run the Justice Department's investigation -- does locate the leakers, to obtain a conviction the prosecution would have to prove that the suspects knew Plame had been working under cover and also knew they were committing a crime by disclosing her identity.

But the national security interest at stake is the protection not only of case officers working in the CIA's clandestine operations but of all their informants and contacts. There is a great likelihood that after Novak revealed Plame's identity, more than one foreign intelligence agency was able to trace whatever front company or organization she may have been associated with and to identify her local sources and contacts.

In the shadow world where human intelligence is gathered -- and Plame has worked on proliferation of weapons of mass destruction -- the careless revelation of a case officer's identity can have a destructive ripple effect. Continuing operations can be compromised, and sources in other countries may be exposed to arrest, torture, or execution.

Deterrence, not mere legal punishment, should be the primary aim of any action the Bush administration takes in response to a blow struck by one of its own against the national security. The letter from the former agency officers spoke of a congressional investigation that could "send an unambiguous message" that members of the intelligence community must "never be turned into political punching bags."

But nothing could do more to deter future saboteurs of the war on terrorism than a demonstration of decisive leadership by the president himself. Bush should demand that the leakers reveal themselves to him before the FBI finds them. And then he should fire them, whoever they are, and tell the public what harm they have done.