Political scientists Dominic Tierney and Dominic Johnson argue that two supposed American failures -- the 1968 Tet Offensive in Vietnam, and the Somalia mission of 1992-93 -- were actually successes.

It's just no one thought of them that way.

An excerpt from the NYT commentary:

The Tet offensive was an unmitigated disaster for the communists. Despite the advantages of surprise, the South Vietnamese insurgents, the Vietcong, failed to hold on to a single target in South Vietnam and suffered staggering losses. Of the 80,000 attackers, as many as half were killed in the first month alone, and the Vietcong never recovered. The United States had clearly won this round of the war.

Yet most Americans saw the Tet offensive as a failure for the United States. Approval of President Lyndon B. Johnson’s handling of the war slipped to a low of 26 percent. Before Tet, 58 percent of Americans described themselves as “hawks” who wanted to step up American military involvement in the war, while 26 percent described themselves as “doves” seeking to reduce it. Two months after Tet, doves narrowly outnumbered hawks.

How did perceptions become so detached from reality? A key factor was overblown expectations. In the months before Tet, Johnson had begun a “progress campaign” to convince Americans that victory in Vietnam was just around the corner. Reams of statistics showed that infiltration rates were down and enemy casualties were up. And it worked. Public confidence ticked upwards. But after Johnson’s bullish rhetoric, Tet looked like a disaster. The scale and surprise of the offensive sent a shock wave through the American psyche. As Johnson’s former aide, Robert Koner, later recalled, “Boom, 40 towns get attacked, and they didn’t believe us anymore.”

The illusion of defeat was heightened by two powerful symbolic events. First, the communists attacked the American Embassy in Saigon. It was one of the smallest-scale actions of the Tet offensive, but it captured America’s attention. The attackers had breached the pre-eminent symbol of the United States presence in South Vietnam: if the embassy wasn’t safe, nowhere was. News outlets reported that the embassy had been captured when in reality all of the attackers were soon lying dead in the courtyard.

Gen. William Westmoreland, the commander of the American forces in Vietnam, held a press conference at the embassy to announce that Tet was an American victory. But behind the general, dead Vietcong were still being dragged away from the blood-spattered lawn. Reporters could scarcely believe what they were hearing. Said one: “Westmoreland was standing in the ruins and saying everything was great.”

Second, Eddie Adams’s photograph of South Vietnam’s police chief executing a Vietcong captive in the street caused a sensation. After he fired the shot, the police chief told nearby reporters: “They killed many Americans and many of my men. Buddha will understand. Do you?” Back home in the United States, the image spoke powerfully of a brutal and unjust war. For some Americans, this image was the Tet offensive.

The big finish:

What does this mean for Iraq? At the least, Tet and Somalia suggest we should be very careful before concluding that Iraq is a defeat. There is real evidence of failure, especially the escalating sectarian violence. But our perceptions are nevertheless easily manipulated. Iraq looks like a defeat in part because the Bush administration fell into the same trap as President Johnson: raising expectations of imminent victory by declaring “mission accomplished” before the real work had even begun. And as with Somalia, fighting shadowy insurgents in Iraq while propping up a weak government engenders negative memories of Vietnam.

Perceptions of success and failure can change the course of history. Reeling from the supposed disaster at Tet, the United States began to withdraw. Memories of “failure” in Somalia were a major reason — perhaps the major reason — that the United States did nothing to stop the genocide in Rwanda in 1994. If Iraq is perceived as a failure, it is only a matter of time before America pulls out, leaving who-knows-what behind. With the stakes so high, Americans must be certain that their perception of failure in Iraq is not a mirage.