Pierre L'Enfant, in his plan for Washington, DC drawn up in 1792, designated a spot midway between the Capitol Building and the White House, about five hundred yards north of Pennsylvania Avenue, for a pantheon for Republican heroes. Washington City, like American democracy itself, has been an unfinished work in progress for much of its history; Charles Dickens called it 'the City of Magnificent Intentions... public buildings that need but a public to be complete'. Forty years after his plan, the site of L'Enfant's pantheon finally received a majestic addition in the form of the government's Patent Office Building. The go-ahead expansionism of Jacksonian America threw out the commemoration of the old, preferring instead to look to the future in the display of American inventiveness; mechanisms, not men, were on display. The Patent Office was designed and built by America's first great architect, Robert Mills, and its neo-classical colonnade - the building's stateliness - worked to exemplify how the busy-ness of Americans would be exemplified, and structured, in the construction of a thriving Republic.

Yet the very stateliness of the building (its gigantic Model Hall was at one point the largest room in America) worked against the society it was meant to represent: the building could not keep pace with the speed and fluidity of nineteenth-century expansionism. Hence, the building was adapted to other purposes: it was a hospital during the Civil War, housed a random variety of government offices for a century, and was threatened with ...