The United States government is suffering from a curious learning disability when it comes to Iraq. As it begins the painful process of disengaging from Iraq, the U.S. is at risk of repeating the mistakes it made going into the war.

This is particularly curious because such a strong consensus has developed about the mistakes made going in. Liberals and conservatives, Republicans and Democrats, defenders and critics of the decision to go to war have all settled on the same list of errors: Not sending enough troops; not anticipating correctly the training and armor that the troops would need; dismantling the Iraqi army; failing to prevent the looting; purging Baath Party members from government jobs, thus leaving thousands of Iraqi families without income and important agencies bereft of critical personnel; misreading the nature of the enemy; underestimating the Sunni-Shiite conflict; misjudging the influence of Iran, Syria and foreign jihadists; squandering reconstruction funds and the catastrophic attempt to micromanage Iraq right after the invasion.

Obviously the United States can't recommit all of those specific mistakes, but amazingly, the assumptions that led to them are still intact, and still inform the proposals and debates about what should be the next steps in Iraq. Consider:

Overestimating the capabilities of the Iraqi government

Assuming that Saddam Hussein’s government was militarily robust and that Iraq had an effective public sector were central tenets in the planning for the war and its aftermath. Assuming that the current Iraqi government can do far more than it is presently doing underpins current plans aimed at decreasing U.S. involvement there. Both assumptions are wrong.

Four years ago the U.S. government thought that Iraq had weapons of mass destruction, that its armed forces were more capable than they turned out to be, that the country's institutions were more functional and reliable than they really were, that its economy, oil industry and overall national infrastructure were in relatively good shape. In March of 2003 then Deputy Defense Secretary Paul Wolfowitz told Congress, "We're dealing with a country that can really finance its own reconstruction, and relatively soon." His boss Donald Rumsfeld added a month later, "I don't know that there is much reconstruction to do."

They were of course wrong. The combination of a ruthless, corrupt dictatorship and a long international embargo had crippled the country and especially its public sector. Moreover, as the cases of Nigeria and Venezuela exemplify, underdeveloped, oil-rich countries tend to have inefficient public sectors, weak institutions, rotten infrastructure and a bankrupt non-oil economy – even without the damage of international sanctions and a regime like Saddam Hussein’s.

Yet, assuming that the Iraqi government is more capable than it has shown itself to be remains an implicit assumption in current proposals for U.S. policy in Iraq. Many of the proposals rely on the hope that the "Iraqi army will stand up as U.S. troops stand down," that the Iraqis will "pull up their socks," "get their act together," "muster the political will" and so on. It has become common to assume that the Iraqi government has the means and the institutions to carry out enormously complex political, financial and military tasks – the sorts of things that most underdeveloped countries can hardly do.

We've learned in four years that Iraq had far fewer institutional capabilities than most expected – that behind Saddam's gilded palaces and military parades lay a state in shambles. Of course it has been further devastated in the last four years. Demands for government action in Iraq often ignore the fact that they are directed at what is in effect an almost empty shell.

Overestimating the capabilities of the U.S. government

Similar caution is in order regarding the U.S. government. We seem permanently deluded that the government has access to unfathomable amounts of money, the most advanced technologies, and is run by a well-staffed bureaucracy educated by the world's best university system. Obviously, these advantages were not enough to run the Iraq operation effectively – or the response to Hurricane Katrina, for that matter.

So in Iraq, a Pentagon funded by a budget that exceeds the combined defense spending of the world's 15 top military-spending nations has been unable to contain ragged Iraqi militias that rely on improvised explosive devices. Recently, General David Petraeus, the U.S. commander in Iraq, famously admitted that "There is no military solution to a problem like that in Iraq, to the insurgency of Iraq."

Unfortunately, the U.S. government has not performed very well in delivering non-military solutions either. The avalanche of books that catalog the blunders made by American civilians in Iraq should give us pause when leaders propose new strategies whose success would depend on the nation-building, democracy-promoting prowess of the U.S. government.

Disdaining diplomacy

Working with others is never easy. Working with others that are foreign governments is often infuriatingly difficult. Others are not just different; they also have different interests. Foreign governments rarely have the same interests Americans have.

Perhaps this truth lay behind the Bush administration's preference for unilateral action, including its decision to invade Iraq. The existence of a British contingent and a handful of troops from 47 other countries in Iraq did not alter the fact that this was an American war. Partly as a result, America finds itself essentially alone in dealing with Iraq today – militarily, politically and financially. At this point even the Bush White House would like to have more actively engaged foreign allies to help in Iraq. The sort of coalition George H. W. Bush built for the first Gulf War in 1991 must look awfully attractive to this President Bush today, but it's far too late to create such an alliance now.

To its credit, the Bush administration has lately shown more interest in diplomacy to deal with problems like Iran and North Korea. But its decisions and overall strategy in Iraq continue to have a strong unilateral and military bias. The latest tack, "the surge," the only new idea of significance in months, is essentially a military decision (send more troops). This time even the British are moving in the opposite direction. The surge has no foreign support at all.

An approach based less on purely military calculation, one that combined new tactics on the ground with bold international initiatives, might have brought some goodwill and assistance to the U.S. at a time when the country desperately needs international solidarity. True, at this point the idea of a diplomatic solution in Iraq may be as unrealistic and naive as a military one. The political costs to foreign leaders of appearing too close to President Bush have become substantial. But isn't it revealing that even after three years of persuasive demonstration that the military is not the solution to Iraq's quagmire, the US is relying almost exclusively on the deployment of more soldiers to stabilize the situation?

Perhaps there is a certain logic to relying on an agency whose annual budget is close to $600 billion – the Pentagon – rather than on one whose budget is a paltry $10 billion – the U.S. State Department. Moreover diplomacy can be unsavory and often involves painful compromises with hard-to-trust foreigners.

There's that learning disability again. We've had four years of war, massive casualties and $500 billion in costs, and to what end? Today, not even the generals seem to think that the military is the main tool for solving the Iraq problem. Yet the administration, the Congress, and a great many commentators all seem to ignore the obvious, powerful lesson.

The conditions set by House and Senate Democrats in exchange for their approval of additional funds for the Iraq war are all about setting complex goals – "benchmarks" – and tight deadlines for the Iraqi government. The House Democrats declare that "Iraq will take responsibility for security in all provinces" and "spend 10 billion in job creating projects." No explanation is given as to how these goals might actually be achieved, and none of the bills clearly articulates how to incentivize other countries to help. The Democrats seem to have learned little themselves from years of unilateral, Pentagon-dominated actions in Iraq.

According to the National Center for Learning Disabilities, "A learning disability is a neurological disorder that affects the brain's ability to receive, process, store and respond to information." This definition naturally refers to learning disabilities in individuals. Its causes are diverse and not yet completely understood. In the case of governments and political systems that are learning disabled, it seems plausible to suspect that the disability is closely related not to neurological disorders but to election cycles. Too much political power without sufficient countervailing checks and balances also breeds arrogance among leaders. This surely contributes to their inability to acknowledge and learn from their mistakes. But what is interesting here is that erstwhile all-powerful leaders don’t seem to be alone in their failure to learn from the recent past. Their opponents also share similar blind spots.

In individuals, one clear symptom of a learning disability is "a distinct gap between the level of achievement that is expected and what is actually being achieved." Alas, this perfectly applies to the American performance in Iraq.

Moisés Naím is editor in chief of Foreign Policy magazine.

This article originally appeared in PostGlobal.