This week marks the fifth anniversary of Congress’s vote to authorize the overthrow of the government of Iraq by military force. The consequences of that vote have been disastrous. More than 3,800 US soldiers and 70,000 Iraqi civilians have paid with their lives. If Congress passes Bush’s recent request for additional war funding, which appears likely, the cost of the war will exceed $600 billion. These are among the more measurable tolls of the Iraq War, and they are immense and unforgivable.

When Congress approved the Authorization of Use of Military Force Against Iraq, however, it did more than permit an illegal and unjustified attack on Iraq; it enshrined the Bush doctrine of “preventive war” and intensified a potentially unending “war on terror.” As The Nation warned in its “Open Letter to the Members of Congress” on the eve of the 2002 vote, “The decision to go to war has a significance that goes far beyond the war…. It declares a policy of military supremacy over the entire earth…. It accords the United States the right to overthrow any regime–like the one in Iraq–it decides should be overthrown.” Moreover, by abdicating its duty to declare war, Congress created a leviathan–an executive branch of unbalanced and unaccountable power. With that vote Congress transformed the country from a constitutional republic into an imperial bully led by an imperial President.

The Administration’s excuses for invading Iraq–its ties to 9/11 and Al Qaeda; its weapons of mass destruction–have disintegrated, but the twin concepts of “preventive war” and the “global war on terror” remain. They present not only the greatest obstacle to leaving Iraq but also the greatest threat for escalating war beyond Iraq’s borders, most immediately to Iran.

As in the run-up to the Iraq War, the Bush Administration has rolled out shifting and unverified justifications for strikes inside Iran. And as one of its rationales for targeting the Tehran regime–its supposedly imminent possession of nuclear weapons–was contradicted by the International Atomic Energy Agency’s Mohamed ElBaradei and US intelligence experts (who estimate that Iran is at least five years away from developing a bomb), the Administration skated to its other casus belli: terrorism. Led by George W. Bush, the Administration has accused the Iranian Revolutionary Guards of training and arming Shiite insurgents who have killed US troops in Iraq, which it calls an act of terrorism. Gen. David Petraeus reinforced such claims when he called the Iranian ambassador to Iraq “a Quds Force member” of the Revolutionary Guards. Whatever the truth of these allegations, they are illegitimate grounds for war with Iran. But by declaring Iran an agent of terrorism, the White House may claim that the only approval it needs to strike Iran is the 2002 Iraq War authorization.

That Bush is sounding the drumbeat for a wider war is predictable; that he has once again found an enabler in Congress is gravely disturbing. On September 26 twenty-nine Democrats, including presidential hopeful Hillary Clinton, joined forty-six Republicans to pass the Kyl-Lieberman amendment, which accuses Iran of fighting a proxy war against Iraqi and coalition forces and classifies the Revolutionary Guards as “a foreign terrorist organization.”

We’ve been down this road before, and we must not take one more step. The path back to sanity begins by repealing the Kyl-Lieberman amendment and by passing a resolution sponsored by Senator Jim Webb (lately endorsed by Clinton) that would prohibit the use of funds for military action against Iran without Congressional authorization. But the Webb resolution merely reasserts Congress’s constitutional power to declare war in this particular instance. It does not end the Iraq War, repeal the war authorization, overturn the Bush doctrine of preventive war, curtail the war on terror or reduce our military footprint in the Middle East. Congress must find the will to take such bold measures. If it cannot, the American people must demand it.