http://www.cnn.com/2014/10/16/politics/tsa-pistole-retiring/Transportation Security Administrator John Pistole announced he would resign at the end of the year, saying he planned to work in academica. He was the longest serving TSA administrator in the agency's history.
Assuming President Obama will be able to get anyone through to replace Pistole, my guesses as to who he will (or should) nominate are; Former FBI Deputy Director Sean M. Joyce, Former MTA CEO Joe Lhota,
Former NYPD Commissioner Ray Kelly, Federal Railroad Administrator Joseph Szabo and LAPD Chief Charlie Beck.
