Karl Rove is widely credited with being "Bush's brain." But when it comes to the administration's dangerous and unprecedented expansion of presidential war powers, John Yoo is the President's mouthpiece.

Only 34, Yoo, formerly of the DOJ's Office of Legal Counsel and now a professor at the University of California Boalt Hall School of Law, joins Paul Wolfowitz and Dick Cheney as one of the preeminent if unlikely policy architects in the Bush pantheon. Wolfowitz, the former Defense Undersecretary, was the principal advocate of unilateralism in American foreign policy. One of signatories of the 1998 Project for a New American Century letter calling on President Clinton to depose Saddam Hussein, Wolfowitz authored the controversial draft 1992 Defense Planning Guidance later repudiated by then-President George H.W. Bush. Vice President Cheney, of course, has been the most strident voice of executive privilege. During the uproar over the secret Bush energy plan meetings, Cheney scoffed that "the suggestion that somehow something improper occurred here simply isn't valid" and that to turn over the papers to the GAO would be "setting a terrible precedent."

But it is Yoo whose handiwork is behind virtually every Bush administration attempt to establish unchecked war powers. Beginning with a 2001 Justice Department memo only two weeks after 9/11, Yoo laid the groundwork for holding and torturing terrorism suspects, ignoring the Geneva conventions, launching pre-emptive strikes against perceived enemies and even performing domestic electronic surveillance of U.S. persons within the United States:

...We think it beyond question that the President has the plenary constitutional power to take such military actions as he deems necessary and appropriate to respond to the terrorist attacks upon the United States on September 11, 2001. Force can be used both to retaliate for those attacks, and to prevent and deter future assaults on the Nation. Military actions need not be limited to those individuals, groups, or states that participated in the attacks on the World Trade Center and the Pentagon: the Constitution vests the President with the power to strike terrorist groups or organizations that cannot be demonstrably linked to the September 11 incidents, but that, nonetheless, pose a similar threat to the security of the United States and the lives of its people, whether at home or overseas. In both the War Powers Resolution and the Joint Resolution, Congress has recognized the President's authority to use force in circumstances such as those created by the September 11 incidents. Neither statute, however, can place any limits on the President's determinations as to any terrorist threat, the amount of military force to be used in response, or the method, timing, and nature of the response. These decisions, under our Constitution, are for the President alone to make.

From Abu Ghraib to NSA spying, President Bush's intellectual rationale comes from John Yoo:

• On Torture. In August 2002, Yoo argued that physical torture "must be equivalent in intensity to the pain accompanying serious physical injury, such as organ failure, impairment of bodily function, or even death." For Yoo, mental torture was limited only to psychological harm that must last "months or even years." In the wake of the Abu Ghraib revelations, Yoo took to the airwaves in May and June of 2004 in defense of the administration.
• On Enemy Combatants and the Geneva Conventions. Over the protests of the State Department, Yoo persuaded President Bush in January 2002 to waive the Geneva Conventions and instead recognize Al Qaeda and Taliban prisoners as "illegal enemy combatants" rather than prisoners of war. Three years later, Yoo argued that the President has the authority to hold the prisoners at Guantanamo Bay indefinitely.
• On Secret Detention of Suspects. Yoo has been a vigorous proponent of secret detention of terrorism suspects, both in the United States and abroad. Foreshadowing the uproar over the NSA program, Yoo defended secret detentions of suspected terrorism contacts in the U.S. so as to not allow Al Qaeda "to see the methods that our law enforcement and intelligence agencies are using to catch them."
• On the McCain Anti-Torture Bill. In recent weeks, Yoo, though no longer in the administration, has supported the White House effort to block passage of the McCain anti-torture amendment in the Senate. "While the impulse behind the McCain amendment is worthy", Yoo wrote in November, "McCain's only real effect would be to limit the interrogation of al-Qaeda terrorists."
• On the NSA Domestic Surveillance Program. According to the New York Times, Yoo worked on "a classified legal opinion on the NSA's domestic eavesdropping program."

In his new book, The Powers of War and Peace, Yoo seeks to offer a blueprint for dramatically redefining as limitless presidential war powers. For Yoo, the constitutional concept of "declaring war" is merely a semantic one, an 18th century anachronism by which one nation merely informed its own citizens and another country of a state of hostilities. For a 21st century United States facing non-state enemies in a global war on terror, Yoo insists:

Declarations of war do not serve a purpose in the balance of powers between the president and Congress in wartime...War declarations do not play an important role in the domestic process of deciding on war. Instead, Congress has at its disposal many other powers to balance presidential power in war making. Congress has complete control over the raising, funding, and size of the military.

For Yoo, the Framers in Article I, Section 8 saw a clear distinction between "making" and "declaring" war and would have been "very clumsy draftsmen indeed" had they conflated the two. As a result, in Yoo's view, there are in essence "no limits" on presidential war powers. In this reading, the post-Vietnam War Powers Resolution statute of 1973 is unconstitutional. The invasion of Iraq, or Syria or Iran for that matter, would require no congressional assent. Incredibly, Yoo asserts that the lone role of Congress is at most to serve as a brake, "it can block a president's warmaking simply by refusing to allocate funds for a conflict."

The consensus among constitutional scholars, of course, runs strongly against Yoo. But for a Bush administration bent on exercising unlimited executive authority, Yoo as the apologist for monarchical power in the White House serves the president well. Despite 200 years of precedent to the contrary, Yoo happily concludes, "these decisions, under our Constitution, are for the President alone to make."