Americans have never liked to think of their country as an imperial power. President Bush emphasized that “America has no empire to extend or utopia to establish” when he spoke to graduating cadets at West Point.

Indeed, the United States has never tried to duplicate the territorial holdings of the British or Ottoman empires. That will change if we go to war with Iraq.

The administration is completing plans for U.S. troops to occupy — and democratize — Iraq after Saddam Hussein is ousted. This is a breathtaking project, in a country that has been plagued by violence, coups and dictatorships since it won independence from British rule in 1932.

The Pentagon is preparing for the U.S. military to control Iraq for at least 18 months. U.S. troops would be responsible for policing Iraq (its regular army is likely to scatter) and preventing an orgy of revenge-taking. U.S. officials also will have to figure out a political formula that will satisfy the Iraqi tribes and ethnic and religious communities who will compete ferociously for power once Saddam is gone.

The political transition will be rocky, and U.S. troops will be in the middle. The White House may appoint a civilian to run Iraq, rather than a latter-day Gen. Douglas MacArthur, and there is some talk of handing off Iraq to the United Nations. But no one will doubt who has real political control.

The United States hasn’t attempted such a huge project of overseas rule since the occupation of Japan and Germany. This parallel is cited by those who believe that the United States must take up a new imperial mission: to establish democracy in key areas where it is absent, notably in the Middle East.

The distinguished historian Bernard Lewis, admired by Pentagon civilian leaders, cites three examples in which democracy “was either induced by victorious enemies or bequeathed by departing imperialists” — Germany, Japan and India.

Unfortunately, these examples provide little comfort. The British ruled India for more than 100 years. Enough said.

As for Germany and Japan, we defeated those countries in all-out war, and they surrendered unconditionally. They had no choice but to follow our orders; Germany was facing the Soviets and dependent on U.S. protection, while Japan’s revered emperor ordered his subjects to obey U.S. decrees.

U.S. forces, moreover, had no illusions as to why they were in Tokyo and Berlin. They were remaking the political systems that had tried to destroy the United States. Yes, there was idealism among the civilians who helped devise the new Japanese and German institutions, but it was grounded in realpolitik.

The situation in Iraq will be very different. President Bush told troops at Fort Hood this week that we would enter Iraq as liberators, if we fought, not as conquerors. He also made clear the U.S. military would be there to create some kind of democratic rule.

Wasn’t the purpose of any Iraq war supposed to be to root out weapons of mass destruction? Never mind. Bush’s sentiments are noble, but they contradict one another.

What if the White House wants the troops to stay (to search for WMD, establish democracy, ensure the free flow of oil, etc.) but large numbers of nationalist Iraqis want them to leave? If we aren’t conquerors, what right do our soldiers have to remain?

At a recent conference of Iraqi opposition activists, several told me that a long-term U.S. occupation would backfire. They doubted that America could handle colonial rule.

“The British and the French had colonial establishments,” said Haider Abas, a member of the Islamic Daawa Party. “The Americans don’t have that culture.

“The British and the French knew they were there to serve their own interests. The Americans think they are there to help. When people don’t want them, they don’t understand why.”

If the United States is lucky, Saddam will flee to exile at the last minute, or a coup will remove him once U.S. forces approach Iraq’s borders.

Barring that, if the administration goes to war, it should be prepared to turn political control over to Iraqis soonest, including control of oil. The U.S. military footprint should be made as small as possible as soon as possible.

Direct imperial rule of Iraq will be very risky. Americans aren’t prepared for it, aren’t experienced with it, aren’t cynical enough for it. The American imperium thrived best when it was exercised indirectly.

This is not the time to bring back such rule in the Middle East.

— Trudy Rubin is a columnist and editorial-board member for the Philadelphia Inquirer. Her e-mail address is trubin@phillynews.com.