The National Defense Authorization Act (NDAA) is a bad piece of legislation, but not for the reason most people think. The NDAA has set the political world alight over fears that it allows the U.S. government to arrest American citizens inside the U.S. and then ship them off as terrorists into indefinite military detention without trial.  Reasonable fears, to be sure – except they don’t arise from the NDAA; rather, the power to do just that likely already exists. 

The real problem with the NDAA is that it does nothing to resolve the root, underlying threat to American civil liberties: Congress' abdication of its responsibility to define the standards that govern for whom and when military detention is appropriate.

By passing a law that essentially abdicates responsibility for clarifying that ambiguity, Congress has failed in its basic responsibility to define and protect the legal rights of American citizens.  Senators Levin and McCain are right (if disingenuous) when they claim the NDAA doesn’t change existing law – but this is not something they should be proud of.

Certainly there exists an armed conflict between the U.S. and al Qaeda in which the use of force was duly authorized by Congress in the 2001 Authorization for the Use of Military Force (AUMF).  In 2004, the Supreme Court ruled in Hamdi that the AUMF also activated some of the president’s war powers, including the right to seize U.S. citizens serving in enemies’ armed forces on a foreign battlefield and detain them indefinitely in military custody without trial.  The Court based this ruling on the fact that the war against the Taliban, with whom Hamdi was serving, resembled the kind of traditional war that the laws of war were created to govern.  

What is less settled is whether the AUMF authorizes the detention of American citizens seized in the U.S.  A trio of cases — Quirin (dating back to World War II), and Padilla and Hamdan more recently — have failed to resolve the question of whether the laws of war should apply to al Qaeda members seized here.  Moreover, the Court in Hamdi also warned that certain aspects of the fight against al Qaeda are sufficiently different from a traditional war that the laws of war don't necessarily make sense and may not govern.

Those cases notwithstanding, what is clear is this:  The AUMF does not give the President domestic legislative power; for that a full-blown declaration of war is required, and the AUMF is insufficient to trigger this power. But that is exactly what is at stake in the question at hand: Which set of rules — military or civil — should govern the detention of a U.S. citizen seized here and accused of membership in al Qaeda?  By purporting to entrench the status quo, the NDAA does nothing to clarify the question.

The lack of clarity surrounding the appropriate legal framework comes from the inherent ambiguities in a low-intensity war against a non-state actor that is not limited to a specific battlefield and has no clearly identifiable metrics for victory. 

The laws of war were designed to govern “traditional” wars, in which the armies of states met on the battlefield and in which soldiers wore uniforms clearly identifying themselves as combatants.  As such, their applicability to the detention of suspected terrorists is questionable.  Not only do al Qaeda members not wear uniforms or carry i.d. cards, but, given the decentralized nature of al Qaeda, it is not even clear what constitutes membership. It might be possible that one can be a “member” of al Qaeda simply by believing or declaring oneself to be.  Given the serious questions as to what constitutes involvement with al Qaeda, it is exceedingly dangerous if decisions concerning the indefinite detention of U.S. citizens can be made by the administration without judicial process or review.

To be sure, the nature of international terrorism does not limit the scope of al Qaeda to foreign lands: from Jose Padilla to Major Nidal Malik Hasan to Anwar al-Awlaki, U.S. citizens certainly do join up with their country’s enemies.  And while military detention may indeed be appropriate in such cases, the inherent dangers to our civil liberties this presents is precisely why Congress can and should only abdicate this essential legislative function clearly, through a declaration of war or other appropriate and clear legislative enactment.

It is Congress’s job to determine and delineate the war powers of the President, particularly when those powers affect the rights of U.S. citizens inside the nation’s borders. The unclear nature of the “war on terror” makes it imperative that the legal rules are clear and established in advance of their implementation. 

If Congress believes that U.S. citizens suspected of membership in al Qaeda are the functional equivalent of enemy soldiers, then it should distinctly empower the President to detain them indefinitely. If Congress believes that there are too many complications and difficulties in determining membership or that the risks to civil liberties are too great, then it should prohibit military detention for U.S. citizens seized in the country.

Either way, creating clear laws allows the public to judge—and the Supreme Court to decide—the rectitude and legality of Congress’s decisions and the President’s actions. The current NDAA simply enshrines ambiguity and is little more than political cowardice that shamelessly perpetuates a threat to our liberty.

Manne is a Lecturer in Law, Lewis & Clark Law School and Executive Director, International Center for Law & Economics, Portland, Ore.; Weinberger is Associate Professor of Politics & Government, the University of Puget Sound, Tacoma, Wash.