But a closer reading of the Obama proposal reveals severe flaws that undermine this purpose. First, and most glaring, the authorization will have only a three-year lifespan, after which Congress would have to pass a new law to resurrect the war. No important declaration of war or authorization to use force has ever had such a sunset, because no armed conflict will ever obey an arbitrary deadline. Even the Framers, removed by centuries from our modern battlefield with its non-state enemies and asymmetric tactics, understood this. Alexander Hamilton argued against critics of the Constitution who wanted to impose similar limits on the government’s war powers (such as forcing armies to disband every year): Because the “circumstances that endanger the safety of nations are infinite,” he wrote in Federalist 23, “no constitutional shackles can wisely be imposed on the power.”
Hamilton and our Constitution’s Framers understood that war was so unpredictable that it could not be dictated by rules beforehand. But this is exactly the course on which the White House’s Authorization for Use of Military Force (AUMF) would set the nation. It makes little sense to announce to your enemies in advance when you will stop fighting. A three-year deadline will have the same harmful effects that Obama’s arbitrary withdrawal dates in Iraq and Afghanistan did. Groups and nations opposed to the United States, such as the Taliban in Afghanistan, ISIS in Syria and Iraq, and Iran in the Middle East, will simply wait us out. Or they may employ destructive delaying tactics in the hopes that war-weariness will lead a small minority in Congress to block a reauthorization in 2018. Try to imagine that, on December 8, 1941, President Franklin D. Roosevelt had asked Congress for a declaration of war that would last only three years. It is impossible, because FDR took war seriously and understood that our enemies fight not according to our plans, but according to their own.