Nothing is easier than to second-guess other people's decisions, ignoring the inherent limitations of knowledge, the pressures of circumstances, and the dangers of alternative courses of action.

Americans in all parts of the political spectrum have made serious mistakes about Iraq.

Some have been the mistakes of honorable people -- indeed, mistakes to which honorable people may be more prone than others. Other people have acted with utter dishonor and dishonesty -- the most shameful recent example being the smearing of General David Petraeus as a liar before he had said a word.

Precisely because Congressional Democrats already knew that there had been progress after the troop surge in Iraq -- some of their own colleagues had been there and seen it -- they had to discredit General Petraeus, in order to prevent the American people from knowing it.

Democratic Congressman James Clyburn said it all in an unguarded moment when he admitted that an American victory in Iraq "would be a real big problem for us" in next year's elections.

That is why a general who is putting his life on the line every day in Iraq, and whose efforts are producing some success, has to be called a liar on nationwide television by United States Senators and a traitor in a New York Times ad.

What of the mistakes of the Bush administration?

The book "Mugged by Reality" by John Agresto, based on his experiences as a civilian advisor in Iraq, makes it painfully clear that the attempt to create a democracy in Iraq was the biggest failure of good intentions there and the key to much else that went wrong.

The idea was that democratic nations do not fight each other or sponsor terrorist campaigns against one another. Therefore, if we could create a democracy in Iraq, we would have made a historic contribution to world peace by planting the first democracy in the Arab Middle East.

Over time, the spread of that democracy in the region would successively deprive terrorist organizations of the bases and political support needed to wreak havoc in Western nations.

Perhaps the strongest support for this theory came from the actions of the terrorists themselves, who have poured men, money, and weapons into Iraq on a massive scale, and blown themselves up in suicide attacks, in order to prevent this project from succeeding.

However, as Agresto points out in "Mugged by Reality," democracy has prerequisites -- and those prerequisites are not universal, especially not in Iraq.

Of the various governments in Iraq since Saddam Hussein's regime was liquidated, he argues, the most effective was that of the American occupation authorities and the worst those elected by the Iraqis. Agresto spells this out in detail.

President Bush has rejected the idea that some peoples and cultures are not ready for democracy. He points to the large Iraqi turnout at the elections, despite the threats of terrorists. Everyone wants more freedom, he and his supporters say.

Wanting freedom, however, is not the same as wanting others to have the same freedom you have. Such tolerance is not the norm in Iraq.

Nor was it the norm in Western civilization until after Protestants and Catholics fought each other for centuries before finally realizing that neither could exterminate the other. Sunnis and Shi'ites have yet to reach a similar accommodation in Iraq.

Agresto points out how Americans' organizing the Iraqi government on the basis of competing interest groups made reconciliation harder, if not impossible.

He notes that those who founded the United States organized political power on the basis of territory, so that mutual accommodations among people with different views within given communities were a prerequisite for gaining power.

What recent progress has been made in Iraq has apparently been made by mobilizing traditional local and regional Iraqi leaders and coalitions, not by relying on the democratically elected central government. There may be a lesson there.