One of the enduring images of the recent war in Iraq is a column of M-1A1 Abrams (search) tanks barreling down the streets of Baghdad on a "thunder run," deep into the city. This spring, American tanks in Iraq gave a small reprise of their astounding successes in the 1991 Gulf War.

The superiority of both American and British tanks (and their superbly trained crews) was beyond question. When they engaged Iraqi armor directly, their ability to get off the vital first shot and make it count was decisive.

Iraq is littered once again with the burnt-out hulks of various models of Russian-made tanks. Many of these tanks were destroyed by air strikes, of course. There were far fewer opportunities for tank-on-tank fights this time around in Iraq. Indeed, some experts think that the day of the heavy tank — the so-called main battle tank (MBT) — as the "arm of decision" in warfare may have come and gone.

American tank officers and crews have every right to be proud of their performance in Iraq, but one hopes they also have foresight and the humility to realize they may never again be able to employ main battle tanks in such a relatively benign combat environment. American and British tanks were, as it quickly turned out, immune from air attack. They rarely, if ever, encountered effective, coherent artillery barrages.

And although after action reports may turn up some exceptions, coalition tanks had relatively few problems with skilled infantry antitank attacks. The potential was there — Iraqi forces possessed a large arsenal of shoulder-fired antitank weapons including antitank guided missiles (ATGMs). One of the deadliest ATGMs, the Russian-made AT-14 Kornet (search), had been delivered to the Iraqis by Syria last year (200 missiles and 12 launchers).

As it was, most of the relatively few Abrams tanks knocked out of commission (not "destroyed" as the press often put it) were victims of rocket-propelled grenade (RPG) attacks. Another 30 to 40 Abrams tanks suffered minor damage from RPG hits but were not disabled.

The sight of the massive Abrams on the boulevards of Baghdad was a compelling symbol of coalition victory. But there is a melancholy aspect to that symbolism. MBTs are clanking dinosaurs, ill suited for the "Army After Next" that will fight the "new kind of war" previewed in Operation Iraqi Freedom.

It's no secret that the smaller, more agile army envisioned by Secretary of Defense Donald Rumsfeld (search) and the people around him is now the thing of the day. And while the Abrams is a remarkably fast and formidable fighter once it's on the battlefield, it takes a l-o-n-n-n-g time to get it there.

Weighing in at 55 tons, Abrams tanks cannot be moved quickly in any significant numbers to a theater of operations. They must arrive by ship, a process that can take months. Once in theater, they ideally should be transported to the battle area by rail or on flatbed trucks to save wear and tear on their suspensions, tracks, wheels and rollers.

A big tank is a very deceptive machine. To the unpracticed eye it is a brute force weapon — a lot of steel, a powerful motor and a big gun. In fact, it is one of the most complex pieces of machinery used in war. Inside its hulking silhouette are many complicated and failure-prone systems and subsystems. These interrelated components may be toughened to "milspec," but even that is not foolproof against the tremendous abuse they routinely endure when a tank is in operation:

— Fire control systems, radios, the main gun and the machine guns must be regularly recalibrated because they are subject to vibration and violent knocks.

— The drive sprockets, road wheels and rollers of the track mechanism, the tracks themselves, as well as the bearings on which the ten-ton turret revolves, are subjected to grueling wear because of the sheer weight of the machine.

— All these load-bearing, moving parts must operate in mud, sand, snow, water, and in rough terrain. A good rule of thumb for a tank, even when it is just moving around and not in combat, is at least eight man-hours of maintenance every day — inspection, adjustment, lubrication, replacement and repair.

Attrition of a significant percentage of its tanks is a way of life for an armored division because, in addition to combat losses, there will be a lot of accidents and breakdowns before, during, and after the battle. A tank driver hits an unexpected obstacle the wrong way and loses a track; an engine burns out, or one of the electrical motors that turns the turret fails; a tank slides into a deep ditch, or overturns into a stream. In each instance, the tank is as useless to a force's combat effectiveness as one that has been knocked out by enemy fire.

It must be noted that many of these losses can be recouped. American tank crews are the best in the world. They are made up, after all, of young American men — many of whom have spent weekends, wrench in hand, under the hood of a hot rod or pickup truck. U.S. experience in the modern tank era (World War II to the present) indicates that almost two thirds of combat-damaged tanks can be repaired and put back on the line. Excellent retrieval equipment, skilled repair units and frequently resourceful crews also mean that 95 percent of non-combat breakdowns will be repaired, usually in less than a week. (However, it must be noted that a week delay in combat may be six days too long.)

In combat, tanks are much more vulnerable than is generally thought. This misconception may be partly due to half-formed impressions from World War II, the heyday of the tank. Some of the most important tanks in history, the German Tigers, the Soviet T-34s and the American Shermans, made their debuts then. Great tank battles were fought in Europe, Russia and Northern Africa. The exploits of Field Marshal Erwin Rommel (search) in the African desert, and the famed drive of General George Patton's (search) Third Division armor deep into Europe gave tanks a somewhat mythical reputation they didn't completely deserve.

Fixed in the public mind were ideas, for instance, about tanks being able to storm their way through enemy lines, putting the enemy to flight and clearing the way for the infantry to come in and "mop up." The fact is, for all their mass, their armor, their big guns, their formidable appearance, tanks seldom sweep across the battlefield. Indeed, in classic tank war, most of a tank's movement involves a brutal hide and seek. They search out hiding places — behind the brow of a hill or a sand dune, masked by thick forest — from which they can direct effective fire at enemy tanks.

They generally cannot move without a screen of supporting infantry to help them see what is going on and to protect them from antitank attacks. Skilled infantry, even without antitank guns or missiles, can hide with relative ease from oncoming tanks. They can then make effective attacks on the sides and particularly the vulnerable rear ends of tanks that have unwisely moved ahead of their own infantry support.

I have heard Marines use what they say is an old expression: "killing tanks is fun and easy." And when they are not pressed about by enemy infantry or enduring air attacks, tanks may fall victim to mines.

The fact is, tanks have had a complicated history in the 87 years since they first appeared on the battlefields of Europe during World War I. First envisioned as a method of destroying German "machine gun nests" that were such a deadly plague, tanks captured the public imagination — mechanical monsters, belching fire as they crossed the "no man's land" of what had become a static battlefield.

By the way, a little bit of history here and just a touch of irony regarding those Abrams tanks on Baghdad streets. Tanks were invented by the British, and originally called "land ships." But in an effort to keep their development secret from German spies, they were said to be mobile water tanks for use in Mesopotamia. The name "tank" stuck and, heh, heh, the name Mesopotamia didn't. In the postwar partitioning of the Ottoman Empire, it became Iraq.

The first tanks had some successes (notably at Cambrai, in November 1917) and some egregious failures, one of the biggest being the third battle of Ypres, when 200 British Mark IV tanks were decimated by German artillery as they thrashed helplessly in the muddy moonscape of shell holes between the battle lines. But all in all, as tactics were refined, tanks changed the character of the static trench war, pointing the way to the war of movement that would be so apparent in World War II.

Nonetheless, the first tanks and all those that have succeeded them have been victims of their own very expensive complexity and of the constant development of ever more effective antitank weapons to place in the hands of the individual infantryman. Now, smart bombs and laser-guided weapons make tanks' inherent vulnerabilities even more acute. But they still have a peculiar power to overawe an enemy and to move firepower forward at a critical moment — they are, after all, the modern equivalent of heavy cavalry. It will be a bold and daring commander, indeed, who would remove them from the battlefield.

The author is a contributing editor to TechCentralStation.com where he writes about defense and military technologies.