Occupation, Conquest and the Constitution of the United States of America

Although the American experience of occupation and conquest was similar enough to that of the Europeans for the Americans to invoke European experiences in order to make sense of their own, the peculiarities of the United States of America stand out in any account of those military occupations. One of the most obvious of these, both to the Americans themselves and to contemporary Europeans, was the US constitution. In matters of conquest, occupation and civil war, the ‘very peculiar constitution of this Government’, as Justice Grier put it in the Prize Cases, played a key role. Justice Grier had in mind the bifurcated allegiance of Americans to both the federal government and the individual state of which they were a member, the respective claims of which were then being tested by civil war. The constitution had also shaped how Americans responded to the possibility and then the increasing reality of territorial expansion. At the outset of the process of expansion, with the Louisiana Purchase of massive tracts from France in 1803, Thomas Jefferson had expressed concern that there was no constitutional provision for the impending ratification of the Louisiana Purchase: the ‘general government has no powers but such as the constitution has given it: and it has not given it a power of holding foreign territory, & still less of incorporating it into a Union’. Jefferson was none the less determined to make the purchase and to ‘rely on the nation to sanction an act done for its great good, without its previous authority’. Jefferson's determination upon conquest would later receive the principled sanction of the Supreme Court, holding that the ‘Constitution confers absolutely on the government of the Union, the powers of making war, and of making treaties: consequently, that government possesses the power of acquiring territory, either by conquest or by treaty’. The court promptly added: ‘The usage of the world is, if a nation be not entirely subdued, to consider the holding of conquered territory as a mere military occupation, until its fate shall be determined at the treaty of peace.’ Its concern though was not with occupied territory but with the precise status and form of government of ceded territory.