Presidential politics 173be taken away, and the congressional grant of power may have been explicitly
hedged with all manner of conditions and limitations. The president’s poten-
tial power is greatest, therefore, in those areas where there exists independ-
ent power to act based directly upon the Constitution, although in practice
these constitutional powers will usually have been filled out and augmented
by federal legislation. Most of these powers are to be found in the field of
military affairs and diplomacy, but they also have internal aspects. The presi-
dent can call the state militia – the National Guard – into federal service and
use them to maintain law and order, usually, but not always, at the invitation
of the governor of a state. The president can use federal marshals or, in an
extreme case, federal troops to enforce federal law and the decisions of the
courts. The intervention of President Eisenhower in Little Rock, Arkansas,
in 1957, and of President Kennedy in Alabama in 1961 and in Mississippi
the following year, are good examples. From time to time presidents have
claimed ‘prerogative powers’ to act without statutory authority where the
safety of the nation is involved – usually, it is true, moving quickly to gain ex
post facto congressional approval of their actions.
From time to time presidents have tried to extend their power beyond
the framework set out above. In time of war, presidents have claimed an
authority to act in ways reminiscent of the prerogative powers of the Crown
in Britain, prerogatives which the Founding Fathers were at pains to deny to
the president. Abraham Lincoln suspended habeas corpus during the Civil
War and spent money without congressional authorisation. Franklin Roo-
sevelt made executive agreements with foreign powers during the Second
World War that usurped the authority of the Senate over treaties. During
the Korean War, President Truman tried to assert executive authority dur-
ing a war situation by nationalising the steel industry without the approval
of Congress. President Nixon used his power as commander-in-chief in the
Vietnam War to conduct secret operations in Laos and Cambodia. These
presidential actions have been justified by what has come to be known as the
doctrine of the ‘unitary executive’. This is the assertion that the president
has as much right to interpret the Constitution in his sphere of competence
as the Supreme Court has, a doctrine which goes back to the early days of the
debates about the distribution of governmental powers between the branches
of government.
George W. Bush has invoked the doctrine of the ‘unitary executive’ to as-
sert his right to adopt policies which are not approved by Congress, or in or-
der to avoid the supervision of the courts. Bush has used ‘signing statements’
to attempt to modify or avoid the effect of laws passed by Congress. When
signing a bill passed by both Houses of Congress the president may make a
statement about how the act will be executed. Thus in signing the McCain
Anti-Torture Bill of 2005, designed to outlaw the use of torture by American
troops or other agencies, Bush stated that:
The executive branch shall construe... the Act, relating to detainees,
in a manner consistent with the constitutional authority of the President