ROUGH CUT - NO REPORTER NARRATIONbr br President Barack Obama kept the nuclear launch codes under wraps despite a tongue-in-cheek prompting from satirical tv show host Stephen Colbert to confirm at least one of the numbers.br br He also pushed Obama to rate himself as a great or "the greatest" president. Obama demurred again.br br The president has appeared regularly on talk shows to reach specific constituency groups including young people, who are a key Colbert demographic.br br When Colbert highlighted the president's positive job creation record, he joked that Obama had provided a lot of employment for secretaries of defense.br br "That's boosted our numbers a little bit," Obama replied.br br Under pressure, Secretary of Defense Chuck Hagel recently announced he was stepping down and Obama has nominated former Pentagon official Ash Carter to take his place.br br If confirmed, Carter would be the fourth person to serve in the role under Obama.