In one sense, of course, there is no doubt about it: America is a superpower. In relative terms, the only superpower in the world. Our armed forces dominate the globe. And, in purely economic terms, our power is equally overwhelming.

But I increasingly find myself wondering whether the United States is indeed a superpower in the fullest sense of that word. For one thing (and it is an extremely important thing), in order to be an authentic superpower a nation must want to be one. And there is, it seems to me, increasing evidence that this country, or at least an important segment of its population, simply doesn't want it to be one.

What is a superpower, anyway? It is a country that is immensely powerful in military, economic and therefore political terms. More than a century ago, an American secretary of state defined this nation, during the so-called Venezuelan controversy, in words that left no doubt as to his meaning, at least as far as this continent was concerned: "The United States is practically sovereign on this continent and its fiat is law upon the subjects upon which it confines its interposition."

No question about America's superpower status there! No doubt lay behind that statement about the United States' position, or about its determination to impose its will, by force if necessary.

But that implicit determination to impose America's will by force, if it should come to that, was a key ingredient of the mixture. And so it has always been, with every superpower legitimately entitled to the name. Rome ruled the ancient world -- by force. Great Britain, in the 19th century, was almost (if not quite) equally dominant. And in the 20th century, first Nazi Germany, then the Soviet Union and finally the United States all acquired superpower status by exercising military dominance (followed by all the other kinds) over large areas of the globe. World War II ended Germany's claim to it; the Soviet Union's collapse at the end of the Cold War ended Russia's; and today America stands alone as the sole survivor.

But we are, to say the least, a strange sort of superpower. We haven't won a real war, or participated in winning one, since World War II, 62 years ago this month. We committed ourselves to saving South Korea when it was invaded by the North in 1950, but endured three years of war and 34,000 military fatalities only to settle, in the end, for a stalemate. We struggled to defend South Vietnam against onslaughts from the Communist regime in the North for decades -- only to abandon our protectorate to its attackers and flee in our ships and helicopters in 1975, leaving 48,000 dead on the battlefield.

And now one of our two major parties and (according to the polls) a majority of the American people want to pull out of Iraq, though we have suffered less than 4,000 military deaths there in more than four years of fighting. Does that sound like the attitude of a superpower?

A decent concern for battlefield deaths and other casualties is one of the proper marks of a democracy. But it is time to ask whether the people of the United States have any stomach for the kind of fortitude that is required of a nation that aspires to be a superpower.

I am beginning to suspect that they don't. To be sure, after we have suffered enough humiliating defeats at the hands of tin-pot dictators around the world who think they have our number, this country is probably still capable of reacting with fury and demolishing some major tormentor down the line who goads us beyond endurance. But we will pay a far heavier price for our forbearance than we would if we had consistently behaved as a superpower.