Sometime within the next six months or so, al Qaeda or Saddamist terrorists will attempt a Tet offensive.

No, Middle Eastern mass murderers don't celebrate the Vietnamese festival of Tet, but trust that America's enemies everywhere do celebrate and systematically seek to emulate the strategic political effects North Vietnam's 1968 attack obtained.

This spring marks the 40th anniversary of Hanoi's offensive (yes, 40 years, two generations). It will also mark the umpteenth time American enemies have attempted to win in the psychological and political clash of an American election what they cannot win on the battlefield.

In the course of Tet 1968, North Vietnamese, American and South Vietnamese forces all suffered tactical defeat and achieved tactical victories; that's usually the case in every military campaign. At the operational level, the North Vietnamese Army (NVA) suffered a terrible defeat. As NVA regiments emerged from jungle-covered enclaves and massed for attack, they exposed themselves to the firepower of U.S. aircraft and artillery. The NVA units temporarily seized many cities at the cost of extremely heavy casualties.

However, Tet achieved the grand political ends North Vietnam sought. Tet was a strategic psychological attack launched in a presidential election year during a primary season featuring media-savvy "peace" candidates. "Peace" in this context must be italicized with determined irony; in the historical lens it requires an insistent blindness steeled by Stalinist mendacity to confuse the results of U.S. withdrawal from Vietnam (e.g., Cambodia's genocide) with any honest interpretation of peace.

Reflecting on Tet in a 1989 interview with CBS News' Morley Safer, NVA commander General Vo Nguyen Giap said: "The war was fought on many fronts. At that time the most important one was American public opinion." He added: "Military power is not the decisive factor in war. Human beings! Human beings are the decisive factor." (See Howard Langer's "The Vietnam War: An Encyclopedia of Quotations.")

Giap knew attacking U.S. public opinion was a classic anti-U.S. ploy. In 1864, politically shattering Abraham Lincoln was a key Confederate goal. The Confederates launched limited offensives (Early's attack on Washington) and bitterly resisted Union attacks, particularly in Virginia where Ulysses S. Grant's limited success was achieved at an enormous cost in casualties. The Confederates' political message: "We remain militarily powerful. The Abolitionist Party will never defeat us. Lincoln is a mad man, a dictator, a gangling fool from hinterland Illinois whose war aims are delusional." That message dovetailed (pun intended) with the campaign message of Copperhead Democrats like Ohio's Clement Vallandigham. (The Copperheads were the "peace wing" of the Democratic Party.) In reality the Confederacy was an impoverished wreck split by Union armies. Its only hope was the psychological erosion of Union will.

Sen. Harry Reid, D-Nev., and his ilk, arguably our era's Vallandighams, have already declared Iraq lost. Last week Reid hedged his defeatist rhetoric. However, al Qaeda and Saddamist plotters are betting a deadly spasm of bombs and subsequent media magnification will give Reid a reason "to clip his hedge."

Their "ultimate Iraqi Tet" would feature simultaneous terror strikes in every major Iraqi city. These simultaneous strikes would inflict hideous civilian casualties with the goal of discrediting Prime Minister Nouri al-Maliki's and General David Petraeus' assessments that Iraqi internal security has improved. The terrorists would reduce Iraqi government buildings to rubble. Striking the Green Zone would be the media coup de grace, intentionally echoing North Vietnam's assault on the U.S. embassy in Saigon. Al Qaeda terrorists would also attack Shia shrines. Kidnapping or assassinating of senior Iraqi leaders would be another objective.

Actually executing a genuine Giap Tet-type offensive in Iraq, however, borders on fantasy. On a daily basis Iraq's assorted terrorist organizations and militia gangs want to cause such system-shaking, simultaneous carnage, but they don't because, well, they can't. A Giap Tet requires a level of coordination the terrorists have never exhibited because they simply don't have it. It requires internal Iraqi political support that the terror cadres and militias lack; fear is not a political program.

Still, the terrorists will attempt a series of terror spectaculars, and kill several hundred civilians in the process, because -- in the quadrennial turmoil of an American presidential contest -- sensational carnage that even momentarily seeds the perception of defeat is their only chance of victory.