AUMFs also have legal significance. They buttress the president’s powers and, consistent with Supreme Court precedent, provide legal support when such aspects of war-fighting as electronic surveillance, detention of enemy combatants and use of deadly force against American nationals who have joined the enemy are challenged in court.
One can argue whether Congress’s constitutional power to declare war serves principally to distinguish formally among enemies, friends and neutrals, or has broader effect. However, AUMFs have become particularly important in the aftermath of the 9/11 terror attacks, as federal courts have involved themselves to an unprecedented degree in scrutinizing such activities. The relevant judicial decisions often cite the existence of an AUMF.
Despite the benefits of traditional AUMFs, President Obama’s proposal is fundamentally flawed. Attempting to obtain political cover for his strategy to fight Islamic State, also known as ISIS or ISIL, he has asked Congress to ban “enduring offensive ground operations” and to terminate the authorization after three years.