What Geneva convention?

John Yoo is a high-flying legal scholar and jurist, a professor of law at the University of California, Berkeley, and a scholar of the influential American Enterprise Institute think-tank in Washington. The Powers of War and Peace comes with a profile in The Wall Street Journal identifying Yoo as an important "opinion-maker" because of his role in redefining interpretation of the constitutional powers and limits enjoyed by the executive during war.

Yoo has become a salient political figure following his two-year stint at the Department of Justice from 2001 to 2003, during which time he helped draft some of the most consequential measures issued by the post-9/11 Bush Administration to help the Government defend the US. These legal opinions included those about the applicability or non-applicability of the Geneva Convention to captured terrorist suspects, the implications of the federal anti-torture statute for the treatment of detainees and the legal basis for pre-emptive strikes. When in February 2002 President George Bush announced that the prisoners seized in the Afghan war, alleged to be members of the Taleban or al-Qaeda, were not covered by the rules of the Geneva Convention because they were "unlawful combatants", he drew on a memorandum authored by Yoo. The logic of this analysis was to make the President's decision consistent with the US Constitution but not with international law as expressed in the Geneva Convention.

Underlying these arguments - and other proposals such as the right for the President to order the assassination of terrorist suspects - is a single thesis. The Constitution, in Yoo's view, gives much greater power to the executive than to Congress in respect to foreign affairs, and specifically the conduct of war. Yoo bemoans the fact that too many interpretations of the US Constitution's division of powers "rip the constitutional text from its historical context". For Yoo, this historical context provides the best means to understand what the framers thought they meant when employing certain terms and language.

To pursue his historical methodology, Yoo examines in detail the way in which the framers would have understood constitutional issues about war and peace as members of the British Empire. He gives a useful account of how the power of the purse was won by Parliament and how this instrument became a means of checking executive powers. Yoo interrogates the writings of Locke, Montesquieu and Blackstone about the constitutional division of powers, checks and balances, and the powers of war held by the executive.

He also looks at three other contextual sources: the states' constitutions; the Articles of Confederation; and the debates between the Federalists and anti-Federalists at the time of the Philadelphia Convention and subsequent ratification. He finds that almost all the state constitutions left war-making powers to the executive.

Yoo's analysis leads to two sorts of arguments. First, he finds, in historical reconstruction of the framers' drafting of war powers in the Constitution, a rich basis for determining what these powers consist in.

For instance, taking the constitutional power given to Congress to "declare war", Yoo argues that the contemporary meaning of this phrase was one of clarification and not of initiation. Furthermore, he argues that the Congress retains significant restraints, if its members choose to exercise them, in respect to budgetary limits on executive war and military powers.

Also, as Yoo notes, numerous presidents have deployed American forces without congressional declarations, including such significant engagements as Korea, Kosovo, and arguably Vietnam. (In contrast, Bush requested and obtained statutory approval for launching wars in Afghanistan in 2002 and in Iraq in 2003.) Second, Yoo argues on the basis of the first point that the executive has more power to exercise than hitherto appreciated, and that it is exactly these new powers a President needs to employ in the struggle against terrorism, a new type of war. Thus, in his "constitutional theory of the foreign affairs power", Yoo argues that "earlier scholarly approaches assumed that, in the absence of government action, peace would generally be the default state". September 11, 2001, ended this fanciful presumption:

"The United States must have the option to use force earlier and more quickly than in the past." He argues that globalisation, with the rise of international organisations and treaties, will make these issues pressing for domestic policy in coming years.

Yoo is right to focus on what additional powers should accrue to the executive during periods of crisis such as war. But it is an argument that will be contested because it challenges prevailing views about the separation of powers, privileges a "sovereignty-centred"

anti-multilateralist view of foreign affairs and is openly doubtful about the utility of international law.

Contestation has already occurred. In June 2004, the US Supreme Court struck down, by 6-3, the District of Columbia court ruling that the detainees at Guantanamo Bay had no claim to habeas corpus before US federal courts. The majority opinion concluded that since the US had "complete jurisdiction and control", those held there had a right to be taken before a court and charged or set free. Such a ruling will not have pleased Yoo, since it weakened the sort of exceptional executive authority he thinks is warranted in wartime. However, he may have taken solace from the historical authenticity of one authority cited by the Supreme Court justices. In support of their ruling, the Court used a ruling by Lord Mansfield to the effect that even if a territory of the British Empire was "no part of the realm", there was "no doubt" as to the court's power to issue writs of habeas corpus if the territory was "under the subjection of the Crown".

This was written in 1759.

Desmond King is professor of American government, Oxford University.