Who's calling the shots at the White House?

Take a gander at the title of FoxNews's article on how the Obama administration is, according to Secretary of State Brian Johnson (oops, Hillary Clinton), going to sue the state of Arizona for its new law requiring police to make an attempt to determine immigration status of lawfully detained individuals. One one level, it's odd that the Secretary of State would be commenting on this instead of the Attorney General, but on another, it could be indicative of who is really calling the shots at the White House. It's not the first time this has happened, after all.