The Obama transition team keeps on leaking: word has it that the president-elect will appoint Arizona Governor Janet Napolitano to head the Department of Homeland Security, replacing the controversial Michael Chertoff. The move puts the border governor in charge of immigration and border security. Arizona has a large number of undocumented immigrants. Napolitano, 50, endorsed Obama in early January and became one of his most visible supporters. Sources told Politico the offer is likely to be made, and that Napolitano is expected to accept.