As everyone knows, in the run-up to the invasion of Iraq, President Bush provided several justifications for the invasion, and people were free to select the one that most appealed to them. Let’s examine the most important justifications that the president provided us.

Justification One and Justification Two were closely related and were the ones that were incessantly pounded into everyone’s head for about a year — the so-called need to disarm Saddam Hussein of his weapons of mass destruction (WMDs).

Justification One related to Iraq’s supposed breach of UN resolutions that prohibited him from possessing WMDs.

Justification Two related to the U.S. government’s right to initiate a “preemptive attack” in response to what Bush described as an “imminent” attack that Iraq intended to launch on the United States with WMDs.

There was one big problem with Justification One: Only the United Nations, as an organization, has the authority to enforce its own resolutions. If the organization chooses not to enforce its resolutions, which it often does, that is its prerogative. As a member nation of the UN, the United States has no right to unilaterally enforce the organization’s resolutions, even if it believes that the UN is acting irresponsibly in refusing to enforce them.

Ironically, in the aftermath of its invasion of Iraq, the United States now finds itself in the same position the UN was in before the invasion was initiated — serving as an international inspection team desperately scouring Iraq, searching every nook and cranny of the country, in the hope of finding some WMDs that might justify its invasion ex post facto. But with one big difference: While the United States inspects Iraq, thousands of people are dead or maimed today who were alive and whole several weeks ago when the UN was doing the inspecting. Wouldn’t it have been easier to have simply added U.S. officials to the UN inspection teams? Didn’t Iraq invite CIA officials to join the inspection teams?

Nevertheless, keep in mind that the purpose of the war was never to execute a nationwide search warrant on Iraq in the hope of doing a better job of inspecting the country than UN officials were doing. It was to “disarm Saddam” of WMDs that President Bush was “certain” existed. The purpose, he said, was to push out the UN inspectors so that U.S. military forces could immediately head to the sites where the weapons were, so that the United States could “disarm Saddam,” a purpose that was not achieved.

Justification Two — the concept of a preemptive attack — was advanced in order to keep America from being placed in the position of an aggressor nation — that is, a nation that attacks another nation unjustifiably, such as Iraq’s invasion of Kuwait in 1991 or Germany’s invasion of Czechoslovakia and Poland in 1939.

The concept of preemptive attack holds that if one nation is about to attack another nation, the defender has the right to attack first — a preemptive attack. For example, if hundreds of thousands of Chinese military forces were massing on the Mexican border, Chinese ships were 30 miles from America’s east and west coasts, and Chinese officials were making public statements about the need for a “regime change” in the United States, most people, I believe, would agree that the U.S. government would be acting within its rights to initiate a preemptive strike on the Chinese forces.

Was Iraq about to initiate an imminent attack on the United States, with or without WMDs? Despite the horrible fear of Saddam Hussein that U.S. officials engendered in the American people in the year leading up to the invasion, it is clear in retrospect that those fears were absolutely groundless.

As everyone knows, U.S. officials are trumpeting their quick military success against Iraq as proof that the president was right in ordering the invasion of Iraq. But military victory over Iraq was never the issue, was it? The issue was always a moral one: Should the United States join the historical ranks of aggressor nations, even if it is able to do so quickly and with minimal casualties?

And that issue — whether the United States should join the ranks of nations that had waged wars of aggression — turned not on military victory but on whether the United States had initiated the war.

After all, let’s not forget that from a military standpoint, Iraq’s invasion of Kuwait in 1991 and Germany’s invasion of Czechoslovakia and Poland in 1939 were as quick and successful as the U.S. government’s recent invasion of Iraq. Yet those stunning military successes did not alter the wrongful nature of their attacks.

The same principle holds true with respect to acts of bravery or heroism that individual soldiers have displayed on the battlefield during the course of the war. Such acts cannot convert a war of aggression into a just war. After all, many German soldiers in World War II fought with great courage but that did not mean that the war their government was waging was a just one.

Was the United States in danger of an imminent attack by the military forces of Iraq, justifying a preemptive strike? Now that war fever is dissipating from the minds of the American people, the rational mind can reach one — and only one — conclusion: the president misled the American people, either accidentally or intentionally, when he said that he was “certain” that such an attack was about to take place. The United States was never at risk of suffering an imminent attack from Iraq, either with weapons of mass destruction or conventional weapons.

At the risk of belaboring the obvious, Iraqi military forces were in no position to mass at the Mexican border or on American seacoasts. In fact, the truth is that after the devastation associated with some two decades of warfare and economic sanctions, the Iraqi army would not have even been a match for the Mexican army. Moreover, Iraq lacked the airplane or missile capability of sending WMDs to the United States.

Keep in mind that the issue with respect to Justification Two is not whether Iraq possessed WMDs — that issue related to the UN resolutions, which only the UN has the authority to enforce (Justification One). The issue with respect to Justification Two was whether Iraq was about to attack the United States with WMDs, which would have justified a preemptive strike.

“But Saddam might have been able to obtain the necessary technology in the future to accomplish such an attack, or he could have given the WMDs to terrorists to bring to the United States.” Might have been and could have been. But those are different concepts from “imminent attack.” And “might have been” and “could have been” do not justify a preemptive strike or a war of aggression. Only an actual attack or the threat of an imminent attack could morally justify a U.S. attack on Iraq, and Iraq never fell into either category.

Justification Three was the one that was submitted at the very last minute, apparently a hedge in the event that WMDs could not be quickly found: the purpose of the invasion was to “liberate” the Iraqi people from Saddam Hussein’s tyranny and to impose democracy in Iraq.

There are several big problems with Justification Three, however. Attacking a sovereign nation for the alleged purpose of freeing its people from tyranny and imposing a new political system does not remove the war from the category of a war of aggression. After all, what war of aggression couldn’t be justified on that basis? When Germany invaded Czechoslovakia and Poland, its declared justification was to free the Germans living in those countries from the tyranny of the Czech and Polish governments. When Germany invaded the Soviet Union in 1941, one of its declared purposes was to “liberate” the Russian people from communist tyranny.

Moreover, from a moral standpoint, where is the justification for an external power to wage war on a foreign country for the purpose of freeing its citizens from the tyranny of their own government, especially when a natural consequence of the war is going to be the deaths of thousands of innocent people, including ordinary soldiers who will be killed in battle? Shouldn’t the issue of freedom and tyranny be decided by the people within that country rather than by a foreign government? After all, as Jefferson pointed out in the Declaration of Independence, oftentimes people will choose to suffer terrible tyranny because they feel that the consequences of violent revolution are worse, in terms of death and destruction.

Despite the fact that Eastern Europeans and East Germans, who were “liberated” by the Soviet Union in World War II, suffered for some 45 years under cruel and brutal communist tyranny, they were finally able to free themselves peacefully. Who’s to say that they would have been better off with the bombs, missiles, death, and destruction that would have come from a so-called war of liberation? What would have been morally wrong with according the people of Iraq the opportunity and respect to make the same choice that Eastern Europeans and East Germans were given?

Furthermore, while pro-war supporters seem to have embraced Justification Three in the wake of the president’s failure to “disarm Saddam” (Justifications One and Two), that doesn’t necessarily mean that what truly motivated U.S. officials was a deep and profound commitment to “freedom” and “democracy” for the Iraqi people.

Keep in mind the U.S. government has been the principal enforcer of the UN sanctions under which the Iraqi people have suffered for some 12 years. Even while U.S. officials are now calling for the lifting of the sanctions in conjunction with placing control of Iraq’s oil in the Iraqi people’s hands, there is no remorse, no regret, no pain over the terrible suffering those sanctions have caused, including the deaths of an estimated half a million Iraqi children. If such callousness and indifference to Iraqi suffering guided U.S. policy for more than a decade, one might be forgiven for viewing the U.S. government’s recently found commitment to “freeing” the Iraqi people with some degree of skepticism.

Keep in mind also that, contrary to our Founders and ancestors, a terrible anti-immigrant mindset guides modern-day U.S. officials. Thus, the tragic irony: “We love you so much that we’re going to invade your country to free you, even though this will wreak much death and destruction for you, your families, and your country. Yes, it might have been better if we had simply let you escape tyranny and come to live with us in America, which was the policy our American ancestors followed, but that would mean that you would live among us, and we certainly could never degrade ourselves to that extent.”

Furthermore, what has historically characterized the U.S. government’s interventionist foreign policy has not been freedom or democracy for people living in foreign lands but rather the installation of puppet regimes, democratically elected or not. That’s why U.S. officials helped to oust democratically elected leaders in Chile and Iran in favor of brutal dictators who did the bidding of Washington officials. That’s also why U.S. officials overlook the absence of democracy in such countries as Pakistan, Kuwait, Jordan, and Saudi Arabia.

Justification Four was that there were links between Saddam Hussein, Osama bin Laden, and the September 11 terrorist attacks. What was fascinating about the president’s use of this justification was that it caused an extraordinarily large number of Americans to believe that Iraqi pilots were among those who hijacked the September 11 planes, which lacked any factual basis whatsoever. If nothing else, the use of Justification Four proves that the minds of Americans are as malleable under a barrage of government propaganda as those of foreigners have proven to be.

In any event, with respect to Justification Four, it goes without saying that a false justification does not remove the invasion from the category of a war of aggression.

Justification Five was the one that was provided long before the September 11 attacks — the need for a “regime change” in Iraq. Such a justification cannot, however, remove the stigma of a war’s being labeled a war of aggression. After all, didn’t Germany and Iraq justify their invasions in 1939 and 1991 with the need for “regime change” in the countries they invaded?

In sum, Justification One falls by the wayside because the United States, as simply a member of the UN, had no authority to enforce UN resolutions requiring Iraq to destroy its weapons of mass destruction. Justification Two falls by the wayside because the United States was not under threat of an imminent attack by Iraq. Justifications Three, Four, and Five fall by the wayside because, under international law and the war-crime principles established by the Nuremberg War Crimes Tribunal, invading a country for the purpose of “freeing the people from tyranny” or “regime change” or for false reasons cannot — and do not — remove the invasion from the ranks of a “war of aggression.”

Finally, it should be reemphasized that under America’s unique system of constitutional government, only the U.S. Congress, not the president, has the power to declare war and that the president is precluded from waging war in the absence of such a declaration. Thus, since the Congress never declared war on Iraq, not only was the U.S. government’s war on Iraq a war of aggression, it also was unlawful under our form of government.

Even as most Americans embrace their government’s invasion of Iraq, even while blocking out of their minds the deaths and injuries of thousands of innocent people, it is likely that they still have not fully processed the true meaning of what has happened — that our government’s invasion of Iraq has now squarely placed our nation in the historical ranks of aggressor nations and that that “achievement” has profound ramifications for our country, not only politically and economically but morally and spiritually as well. Not the least of these ramifications is the ever-present danger that the president and the U.S. military-industrial complex can now trap the American people into supporting all future U.S. wars of aggression under the rubric, “You might not agree with the president’s decision to go to war but dissent is wrong during wartime and you now need to support our troops.”

Our job is to continue battling for the hearts and minds of our countrymen with our principles, ideas, and ideals, with the ultimate aim of rejecting the alien ideas that now hold our nation in their grip and restoring the principles that guided the founding of our nation — the principles of individual freedom, free markets, limited government, noninterventionism, and republic of our Founders and ancestors.

Mr. Hornberger is founder and president of The Future of Freedom Foundation.