Those are the call signs for Barack Obama and Hillary Clinton respectively. Both have had Secret Service protection earlier than any presidential candidate. Clinton's protection is part of the mandatory detail given to ex-presidents and their families. Other viable candidates for president don't get a detail unless they request one. In fact, John McCain hasn't even put in a request yet. And, according to this Hotline story from last year, candidates get to choose their own call signs. What's McCain's going to be? Is "Maverick" too obvious? Other awesome call signs can be found here.
--Mori Dinauer
