Back in May 1956, columnist Joseph Alsop filed a dispatch from the tiny desert kingdom of Kuwait, which he described as "little more than a vast oil well with a small town on top of it."

Americans didn't know much about Kuwait then, but Alsop considered it a crucial piece of real estate. Dangerous forces were percolating in the Middle East. Egypt's Gamal Abdel Nasser sought to forge a growing sense of Arab nationalism into a weapon against the West. The Soviet Union, snuggling up to Nasser, also sought to exploit Arab nationalism to further its own strategic ends.As Alsop put it: "The Soviet object in the Middle East is simply to use Arab nationalism to bring down the Western alliance by encouraging the Arab states to deny to the West the vital oil on which Britain and Western Europe so absolutely depend."

This perception from the past is worth noting in the context of the current Persian Gulf drama, which began with Iraq's resolve to wipe little Kuwait off the map. With President Bush's expeditionary force growing to 430,000 troops, a home-front question casts a political pall over the operation: Why are we there?

Some suggest it is to deter the military aggression of Iraq's Saddam Hussein. Others say the crucial element is Saddam's emerging capacity to produce weapons of mass destruction. Secretary of State James Baker III has cited U.S. jobs, and Bush has listed, among these other factors, "the brutality of Saddam Hussein."

But one element rises above all others: oil. Oil represents more than material comfort in the West. It fuels not just our cars and power plants but the Western economy itself. It makes possible the economic activity that feeds, clothes and houses the people of the West. It also makes possible the U.S. military, which in turn serves as a force for international stability.

While some argue that the United States could move beyond its dependence on foreign oil through conservation, that thinking ignores America's commitment to the economic well-being of its industrial allies.

Oil is a foundation stone of our way of life and of our strategic position in the world.

And yet many Americans appear uncomfortable with the idea that we would go to war for it. Polls reflect this discomfort; in fact, Americans' acceptance of the oil rationale is plummeting.

In a September poll conducted for The Wall Street Journal and NBC News, 50 percent of respondents listed oil as the chief rationale for Bush's military action, compared with 39 percent who said the primary reason was to repel Iraqi aggression. A month later, 46 percent cited the need to extract Iraq from Kuwait; only 35 percent cited oil.

There is something wrong here, for without the factor of Mideast oil reserves there wouldn't be any huge U.S. Army poised for war on the other side of the world.

It was far different in 1956, as Alsop's column from Kuwait attests. Back then, Kuwait's famous sweet crude supplied two-thirds of the oil for the British Isles, and Kuwaiti sheiks supplied Britain with its largest single source of new capital in the form of recycled oil money.

"In these circumstances," wrote Alsop, "it is not surprising that the British regard the Persian Gulf Sheikdoms, and especially Kuwait, as their hole card."

With the major Arabian kingdoms looking increasingly vulnerable to the specter of Arab nationalism, a serious question hovered over the gulf: Should Britain - and could Britain - maintain that hole card by force?

The dangers were profound. A move to protect Kuwait from Arab nationalism could stir even greater nationalist fervor, Alsop wrote, "and one can foresee all sorts of other very grave troubles, perhaps on the borders here, certainly at Suez, and quite probably at Aden."

Yet there was really only one answer. "The choice," wrote Alsop, "has already been made in London. The sheikdoms will be held, by naked force if necessary."

It never came to that, of course. But clearly the British understood the imperatives of Mideast oil, and its role as the commodity that both signifies and fosters the industrial life of the West.

It is to be hoped that war can be avoided this time, too. But if it should come, it should come accompanied by a clear sense of its purpose and rationale. For a nation that goes to war without such a sense of purpose and rationale is a nation facing an added dimension of risk. The added risk is that it will end up fighting not just the enemy in the field but itself as well.