James Wilkinson
In 1854, following long archival research in the Spanish archives in Madrid, Louisiana historian Charles Gayarré exposed Wilkinson as having been a highly paid spy in the service of the Spanish Empire. In the years since Gayarré's research became public, Wilkinson has been terribly strongly criticized by American historians and politicians. According to President Theodore Roosevelt, "In all our history, there is no more despicable character." However, he has been defended, especially in breaking up the Burr conspiracy.