An article on Obama’s expanding war powers and his legacy. For more from Jack Goldsmith on this topic, listen to his related <a href="http://www.lawfareblog.com/2014/11/the-lawfare-podcast-episode-99-jack-g... target="_blank">Lawfare podcast.</a>

The war against the Islamic State is now illegal. The War Powers Resolution of 1973 gave President Obama 60 days to gain consent from Congress and required him to end “hostilities” within 30 days if he failed to do so. This 90-day clock expired last night.

Obama, who has spent much of his presidency seeking to wean the United States off a perpetual state of war, is now putting forward unjustifiable interpretations of the executive branch’s authority to use military force without explicit approval from Congress.

Some commentators have begun the discussion about whether existing domestic authority would support such uses of force against ISIS, and so we thought it important to join (and reorient) the conversation along two dimensions: (1) to show how implausible the claims are that the 2001 (9/11) and 2002 (Iraq) AUMFs might provide the President with authority to use force against ISIS in Iraq; and (2) to use this debate as an illustration of the dangers of preemptively authorizing the use of force in the absence of specific facts that warrant it.

In practice, presidents usually get their way, and the process often revolves around political power as much as legal considerations.

This report provides historical background on the enactment of declarations of war and authorizations for the use of force and analyzes their legal effects under international and domestic law.

Although existing statutes provide me with the authority I need to take these actions, I have repeatedly expressed my commitment to working with the Congress to pass a bipartisan authorization for the use of military force (AUMF) against ISIL. Consistent with this commitment, I am submitting a draft AUMF that would authorize the continued use of military force to degrade and defeat ISIL.

The White House’s proposed legal authorization for a war against the Islamic State may haunt U.S. foreign policy for years to come.

It may well be that the importance of these resolutions is fading over time as presidents lay bare the fiction that congressional consent is really essential. Still, the resolutions do retain functional importance in several respects.