Of course, there are going to be numerous lessons and consequences of the US-led invasion of Iraq. Many of them will have to do with the nature of decision making, the wisdom of unilateral, or more accurately unsanctioned multilateral, intervention, the problems inherent in intelligence analysis, and other similar issues. However, in two recent article we can see warnings of a lesson we should hope odes not get learned. In the Washington Post, Robert Kaplan warns us that a move back to realism (as evidenced by the appointment of Robert Gates to SecDef) ignores the vital moral element of US foreign policy. And in the Weekly Standard, Robert Kagan and Bill Kristol warn that the dictates of realism demand foreign policy decisions that clash with the interests of the US.
As the appointment of Gates to replace Rumsfeld shows (although Rumsfeld was no neo-con; just a realist convinced in two things: Terrorism as an existential threat to the state, and the need to transform the US military), one of the dominant reactions to the on-going debacle that is Iraq is a return to the basic tenets of realism. As Kaplan puts it, "U.S. foreign policy will be defined by an obdurate caution, coupled with a ruthless, almost mathematical application of balance-of-power principles." According to Kagan and Kristol, a return to realism would mean "the United States should turn a blind eye to Iran's nuclear weapons program, in exchange for Iran's help in easing our retreat from Iraq" and "putting pressure on Israel to deal in a more forthcoming way with the Hamas-dominated Palestinian government. Israel should be induced to make concessions despite the ongoing violence and the refusal of Hamas to ratify even Yasser Arafat's acceptance of Israel's right to exist."
If we learn anything from Iraq, it's that the US must be exceedingly careful if it ever thinks about attempting large-scale coercive nation-building. But that lesson must not force the US to retreat from its liberal mission. The US does not always act in accordance with its principles, but it is unthinkable that the US would NEVER do so. It was the US that rebuilt the shattered European and Japanese states after World War II, it was the US that presses Zimbabwe and Burma to improve their human rights records, it is the US that is standing firm in its refusal to negotiate with North Korea, it is the US that is keeping attention focused on Darfur. And without the security umbrella provided by US military hegemony, issues of human security such as the ICC would be nowhere near the international agenda.
Iraq should, and very likely has, taught the US humility and restraint, both of which are valuable and important to learn. But those lessons must not be taken too far. A retreat to a realist foreign policy would betray the ideals of this country, and would abandon the rest of the world to misery.