The Society for History in the Federal Government has awarded the 2009 James Madison Prize to Gautham Rao for his essay, "The Federal Posse Comitatus Doctrine: Slavery, Compulsion, and Statecraft in Mid-Nineteenth-Century America." The award honors the best article or essay "that deals with any aspect of the federal government's history." The essay appeared in the Law and History Review 26 no. 1 (Spring 2008), and is available to subscribers here.
A general announcement of SHFG awards is here, but a list of 2009 winners has not yet been posted. Hat tip: David Tanenhaus.