WASHINGTON -- White House spokesman Robert Gibbs and President Barack Obama share the same trait: They both are very cautious when speaking with reporters. Gibbs measures his words hesitantly between some "ums" and "ahs," before voicing carefully selected words in response to a reporter’s question. As White House press secretary he is in the bull’s eye every day at televised news briefings, which may explain why he appears most comfortable with the reporters for wire services and TV networks he schmoozed with on the campaign trail. In a position where many predecessors have blown their tops out of frustration or...