The central role played by Russian tanks in occupying one-third of Georgia in only five days teaches a very sobering lesson: The major wars of the 21st century will be a lot more like World War II than most fashionable pundits and military theorists have dreamed.

Therefore the for-so-long out-of-fashion artillery, infantry and armor specialists in the U.S. Army and the handful of unfashionable and old-fashioned military analysts who support them turned out to be right after all.

There is no substitute for having large numbers of troops on the ground to fight battles, occupy territory and make sure it stays pacified afterward. And there is no alternative to having the artillery and Main Battle Tank forces to produce classic Carl von Clausewitz concentrations of power and decisive ground route axes to win battles and conquer countries.

"Girlie" high-tech systems can't do any of that, and air power can be effective only when it is integrated with old-fashioned ground power.

These tough, ugly, uncompromising old truths also flatly contradict a lot of the Conventional Wisdom of the past 60 years about the nature of war.

Tanks proved pretty irrelevant -- though not totally so -- to most of the anti-colonial conflicts of the 1950s and 1960s. France enjoyed overwhelming conventional military power in Algeria throughout the long and ferocious War of Algerian Independence from 1954 to 1962 -- arguably the bloodiest and certainly most ferocious of all modern anti-colonial uprisings. Similarly, having a monopoly on armored power did not allow the British to crush the anti-colonial uprisings that drove them out of Mandate Palestine, Cyprus, Kenya or Aden in the quarter-century after the end of World War II.

However, even then, an exception to this pattern was the Vietnam War.

The U.S. Army effectively destroyed the Viet Cong as a combatant guerrilla force in its successful response to the Tet Offensive of 1968 -- a brilliant tactical military success for the United States that was transformed by poor reporting and analysis and loss of nerve by President Lyndon Johnson into a major strategic defeat. But when the North Vietnamese army -- which took up the burden of the war from the shattered Viet Cong after Tet -- finally conquered South Vietnam in 1975, it did so thanks to its overwhelming armored ground superiority in Main Battle Tanks supplied by the Soviet Union. It was on tank treads that the NVA rolled into Saigon.

Two other conflicts of the 1970s confirmed the continuing crucial supremacy of tanks to ground conflict and the survival or utter conquest of nations. The Israelis at the beginning of the 1973 Yom Kippur War or War of Ramadan suffered very heavy casualties at the hands of handheld anti-tank rockets used in large numbers by Egyptian infantry. But it was armored battles in the Sinai Desert and the Golan Heights that preserved the existence of the state of Israel and that ultimately defeated the Syrian and Egyptian armored hosts arrayed against it. Six years later the Soviet Red Army rolled into Kabul, Afghanistan, in December 1979 with insouciant ease.

U.S. armored forces showed their excellence and crucial importance in the two Gulf War victories against Iraq in 1991 and 2003. However, when U.S. forces occupied Iraq after the 2003 invasion, they found themselves rapidly sucked into dealing with an enervating counterinsurgency war against Islamist guerrillas that led to a full-scale Sunni Muslim vs. Shiite Muslim civil war by the start of 2006. These were conflicts that having the best armored force in the world could not prevent or resolve.

As a result, the importance of having large and technically superior tank forces became unfashionable in the United States in the years following the 2003 conquest of Iraq. But the Russian army's rapid success in Georgia should remind U.S. policymakers just how important it still is to have large armored forces to project power on the ground.