Steven Weisman, writing in the NYT (Jan. 18, 2004):

The American occupation in Iraq has been one of relentless trial and error....

Yet all these examples may not be so different from what has happened throughout American history, especially as administrations have sought to wage war or confront grave crises.

"It's nice to think that when there is a challenge, the United States goes in with a well-formulated plan and sticks to it," said John Lewis Gaddis, a professor of history at Yale. But "there is no historical precedent for that happening. Germany and Japan after World War II were textbook examples of successful occupations, but they did not proceed according to a predetermined, consistently applied blueprint. Far from it."

Indeed, American rule in both Germany and Japan were bedeviled by a problem that now faces American authorities in Iraq. Both postwar occupations began with the idea of purging the leaders of the old regimes, just as the United States set out in Iraq with a plan to remove top members of the Baath Party of Saddam Hussein. The initial plan in both Japan and Germany was to prevent the re-emergence of an industrial state that could nurture a new generation of Nazis and militarists.

Quickly, however, American anxiety shifted from resurgent Nazism to the spread of Communism in Europe and Asia. Reversing themselves, American authorities began working with former Nazis, especially in the intelligence services, who knew where the Communists were lurking. Even more important, the plan envisioned by Treasury Secretary Henry Morgenthau to turn Germany into a pastoral state was dropped, replaced by a decision to restore its economic strength to block Russian ambitions west of the Iron Curtain.

In Japan, the beginning of the Korean War "ushered in a new world," writes John W. Dower, a professor of history at the Massachusetts Institute of Technology, in his book about the American occupation, "Embracing Defeat." Citing a popular movie about a man arrested for stealing who confesses by saying, "Oh, mistake!" Mr. Dower writes that "Oh, mistake!" became a famously sarcastic phrase applied to the occupation as it sought to remilitarize Japan, work with members of the old regime and re-establish its economic power....

"We went in the Philippines in 1898 and decided to stay, while surrounding that decision with a lot of the same kind of rhetoric that surrounded the Iraqi invasion," said David M. Kennedy, a professor of history at Stanford. "We were going to lift them up and usher them into the family of nations. But as soon as we got there, it turned out the Filipinos had ideas of their own."

Instead of lifting the Philippines up, the Americans found themselves having to suppress an insurrection, at a cost of more than 4,000 lives. Subsequently, the United States convinced itself that it had to remain in the Philippines to protect its strategic interests in Asia, while in Cuba the desire was to stay to protect American investments.

Moreover, just as the United States is today debating the rationale of the Iraq war, it once debated the purpose of possessing colonies. "There was a lot of confusion about American objectives," said Bruce J. Schulman, a historian at Boston University. "Were we protecting our investments? Promoting democracy? Keeping other imperial powers away? Freeing the Cuba and the Philippines from Spain? There was a seat-of-the-pants approach to everything we did."

Still another example of chaotic planning that seems smooth only in retrospect related to the Marshall Plan, announced in 1948 as the American effort to rebuild Europe, including Germany. One of its twists and turns was how the United States could look evenhanded and offer aid to the Soviet Union and its satellites, while making the terms so strict that they would refuse the aid. The terms of the Marshall Plan were constantly shifting as a result.

"If you read Dean Acheson's memoirs, or anything else that was contemporaneous and honest, you are always surprised to see how much was improvised," said William Kristol, the editor of The Weekly Standard and supporter of the war in Iraq. "There have to be adjustments on anything on the scale of Iraq. The problem is that the Bush administration has an aversion to admitting that they are changing course."

Despite the temptation to see history as an inevitable chain of events, the course of decision-making never has run smooth. "If you look at American foreign policy day to day or week to week or year to year, it almost always looks terrible," said Walter Russell Mead, a senior fellow at the Council on Foreign Relations. "But if you take the long view, we seem to do better at foreign policy than other people. And we tend to win. Historians and obviously pundits tend to focus on the mistakes. You could read a lot of history of the cold war, for example, and not realize that we won it."