Ten years since the Iraq war began, many of the most important lessons from the debate before and during the war have yet to be learned. Most Americans are now well aware of the Bush administration’s terrible mismanagement of the war, its dishonest pre-war propagandizing, its utter lack of planning for Iraq after the invasion, its ideological blindness to the culture and history of the country, and its delusional vision of the regional democratic transformation that would follow regime change. There are valuable lessons to be learned from all of these failures, but these things can obscure the deeper flaws in U.S. foreign-policy debates that greatly increase the chances that the U.S. will make similarly disastrous blunders in the future.

Following the end of the Cold War, American hawks have felt compelled to build up every minor threat as a new global menace to replace the vanished Soviet Union. That has inevitably required grossly exaggerating the danger to the U.S. and the rest of the world from third- or fourth-tier states. The fear-mongering about Hussein’s Iraq in 2002-03 was one of the more extreme and absurd examples of this since there were few states in the world that posed less of a threat to America than a broken-down, disarmed, impoverished, and internationally isolated dictatorship. The idea that the U.S. was being “forced” to go to war was preposterous at the time, and in hindsight it appears even more so.

Unfortunately, the experience in Iraq hasn’t taught most Americans to stop imagining manageable threats to be intolerable, “critical” ones. A recent Gallup poll found that over 80 percent of Americans believed North Korea and Iran’s nuclear programs represent a “critical” threat to “vital” U.S. interests. The Iraq War likely wouldn’t have happened if there were not a broad, bipartisan tendency to exaggerate the scale and nature of foreign threats, and that tendency has not noticeably weakened in the last ten years. Despite the reality that the U.S. is more secure now than it has been in many decades, our foreign-policy debate is filled with as much alarmism and threat inflation as ever.

Instead of learning that containment and deterrence are wiser—and cheaper—than preventive warfare, American leaders seem to have concluded that “prevention” is the only possible way to respond to possible Iranian nuclear proliferation. As long as “prevention” remains official U.S. policy towards Iran, it will be difficult to avoid war at some point in the future. The Bush administration bears most of the responsibility for invading Iraq, but it couldn’t have done so without the overwhelming, pre-existing consensus in favor of regime change. Just as making regime change in Iraq official U.S. policy laid the groundwork for the later war, ruling out containment of Iran puts the U.S. on the path to another unnecessary and costly conflict.

The lack of Iraqi WMDs made a mockery of the official justification for the invasion, but it obscured the truth that Iraq was at most a minor threat to the U.S. even if it had possessed the weapons programs it was accused of having. Overthrowing Hussein then gave other “rogue states” strong incentives to try to acquire nuclear weapons as a deterrent. While American hawks have seemingly lost all faith in the power of deterrence, pariah states have concluded that Hussein’s mistake was in disarming. Far from bolstering the nonproliferation regime as its supporters claimed it would, the Iraq War did enormous damage to it by confirming would-be proliferators’ worst fears that the U.S. will first seek to disarm them and then topple them.

Most Americans have yet to learn that preventive wars aren’t a legitimate form of self-defense. Advocates for military action against Iran may describe it as “anticipatory self-defense,” but there is no way to distinguish between a preventive war waged in “anticipatory self-defense” and an unprovoked war launched to batter another state into submission or to overthrow its government. Endorsing preventive war as self-defense means that the U.S. reserves the right to attack another state that might potentially threaten it in the future. Americans have not yet grappled with the implications of what this means.

The pre-war debate should have taught us that moralizing in foreign policy is no substitute for sound analysis and argument, but it hasn’t. Moralizing rhetoric was often the bludgeon that war supporters used to quash skepticism and impugn the motives of opponents, and it remains the same now. To doubt the wisdom of waging a war of choice for regime change was treated as the equivalent of celebrating Baathist dictatorship and apologizing for Hussein’s atrocities. The same moralizing frequently dominates our foreign policy debates whenever authoritarian governments are involved: opposing unwise, interventionist policies directed at a certain country is equated with sympathy for the regime and hostility to America. There is almost nothing more detrimental to rigorous and informed policy debate than this despicable tactic, but, as the spectacle of Chuck Hagel’s confirmation hearings showed, American politicians and pundits still use it as freely and often as if the Iraq War had never happened.

Most politicians, policymakers, and pundits continue to have huge blind spots that cause them to overlook the humanitarian consequences of coercive U.S. policies. When assessing the costs of the Iraq War, the 130,000+ dead Iraqi civilians, the millions of Iraqis displaced or forced to flee their country, and countless others adversely affected by the war are often left out of the story altogether. They and their countrymen will continue to bear the costs of the war long after Americans and Europeans have turned their attention elsewhere. Perhaps the most important unlearned lesson from the war is that many Iraqis are worse off today than they were ten years ago.

Daniel Larison is a senior contributor to TAC and blogs here.