I hope the Republican Congress will take up the President’s proposal on Monday night to declare war on ISIL, or Islamic State (IS). As discussed by Ilya Somin and Mike Ramsey, the better constitutional view is that, with narrow exceptions, armed conflict must be authorized by Congress. The previous authorization for war, which came after 9/11, does not clearly concern IS, which did not exist in 2001. Although IS may have grown out of some elements of Al-Qaeda, it is not obviously the kind of organization connected to the 9/11 attacks  to which the Authorization for the Use of Military Force of 2001 continues to apply.

A war resolution also would provide greater long-term credibility to the United States’ commitment to fight IS. With little more than a year remaining in his second term, President Obama is now a very lame duck. Getting Congress on record would show our allies that we are in this fight for the long haul.

And importantly, a congressional declaration of war against IS would also strengthen the case for treating those who pledge allegiance to IS, such as the terrorists of San Bernardino, as enemy combatants, who are subject to military justice for war crimes and to more summary procedures at trial. They would not receive the right to counsel at the time of arrest or other benefits of the American criminal justice system that can interfere with the gathering of timely intelligence. Ex Parte Quirin – the World War II case that upheld military tribunals for American saboteurs working for Germany – makes clear that such treatment is legal. But its holding may well depend on the fact that the United States had declared war against the Axis powers for which those enemy combatants fought.

I am not advocating the kind of enhanced interrogation techniques authorized by the Bush Administration.  But there is a substantial gap between Miranda warnings and waterboarding and it is a gap which can be exploited to our advantage to gain intelligence. At present we lack sufficient human intelligence to inform the war on terror, particularly as the Obama Administration has shifted to a drone strategy that kills rather than captures terrorists.

The Obama administration unfortunately has been wedded to the contrary view that the American justice system is generally the place to prosecute people who commit atrocities like the massacre in San Bernardino, even when they are fighting for foreign terrorist organizations. Through an authorization of war, Congress could require that adherents of IS be prosecuted for war crimes and interrogated as enemy combatants, unless the Secretary of Defense declared that it was in the overwhelming national interest to prosecute them in United States courts. The President would be hard pressed to veto a Declaration of War that contained such provisions