Of course Katharine Gun was free to have a conscience — as long as it didn't interfere with her work at a British intelligence agency. To the authorities, practically speaking, a conscience was apt to be less tangible than a pixel on a computer screen. But suddenly — one routine morning in early 2003, while she was scrolling through e-mail at her desk — conscience struck. It changed Katharine Gun's life, and it changed history.

Despite the nationality of this young Englishwoman, her story is profoundly American — all the more so because it has remained largely hidden from the public in the United States. When Katharine Gun chose, at great personal risk, to reveal an illicit spying operation at the United Nations in which the U.S. government was the senior partner, she brought out of the trans-Atlantic shadows a special relationship that could not stand the light of day.

By then, the president of the United States — with dogged assists from the British prime minister following close behind — had long since become transparently determined to launch an invasion of Iraq. Gun's moral concerns were not unusual; she shared, with countless other Brits and Americans, strong opposition to the impending launch of war. Yet, thanks to a simple and intricate twist of fate, she abruptly found herself in a rare position to throw a roadblock in the way of the political march to war from Washington and London. Far more extraordinary, though, was her decision to put herself in serious jeopardy on behalf of revealing salient truths to the world.

The e-mailed memorandum from the U.S. National Security Agency that jarred Katharine Gun that fateful morning was dated less than two months before the invasion of Iraq that was to result in thousands of deaths among the occupying troops and hundreds of thousands more among Iraqi people. We're told that this is a cynical era, but there was nothing cynical about Katharine Gun's response to the memo that appeared without warning on her desktop. Reasons to shrug it off were plentiful, in keeping with bottomless rationales for prudent inaction. The basis for moral engagement and commensurate action was singular.

The import of the NSA memo was such that it shook the government of Tony Blair and caused uproars on several continents. But for the media in the United States, it was a minor story. For The New York Times, it was no story at all.

In a time when political players and widely esteemed journalists are pleased to posture with affects of great sophistication, Katharine Gun's response was disarmingly simple. She activated her conscience when clear evidence came into her hands that war — not diplomacy seeking to prevent it — headed the priorities list of top leaders at both 1600 Pennsylvania Avenue and 10 Downing Street.

Marcia and Thomas Mitchell, the authors of the new book "The Spy Who Tried to Stop a War," describe the scenario this way: "Twisting the arms of the recalcitrant (U.N. Security Council) representatives in order to win approval for a new resolution could supply the universally acceptable rationale." After Katharine Gun discovered what was afoot, "she attempted to stop a war by destroying its potential trigger mechanism, the required second resolution that would make war legal."

Instead of mere accusation, the NSA memo provided substantiation. That fact explains why U.S. intelligence agencies firmly stonewalled in response to media inquiries — and it may also help to explain why the U.S. news media gave the story notably short shrift. To a significant degree, the scoop did not reverberate inside the American media echo chamber because it was too sharply telling to blend into the dominant orchestrated themes.

Overall, to the editors of American mass media, the actions and revelations of Katharine Gun merited little or no reporting — especially when they mattered most. My search of the comprehensive LexisNexis database found that for nearly three months after her name was first reported in the British media, U.S. news stories mentioning her scarcely existed.

When the prosecution of Katharine Gun finally concluded its journey through the British court system, the authors of the new book about her note, a surge of American news reports on the closing case "had people wondering why they hadn't heard about the NSA spy operation at the beginning."

This column was adapted from Norman Solomon's foreword to the new book "The Spy Who Tried to Stop a War" by Marcia and Thomas Mitchell. Norman Solomon is the author of "War Made Easy: How Presidents and Pundits Keep Spinning Us to Death." The book has been adapted into a documentary film of the same name. COPYRIGHT 2008 DISTRIBUTED BY CREATORS SYNDICATE, INC.