(Note: The following remarks were delivered October 21 at the Center for Security Policy and have been slightly edited for length.)

Most anyone who is given responsibility in matters of national security quickly comes to appreciate the commitments and structures put in place by others who came before. You deploy a military force that was planned and funded by your predecessors. You inherit relationships with partners and obligations to allies that were first undertaken years and even generations earlier. With the authority you hold for a little while, you have great freedom of action. And whatever course you follow, the essential thing is always to keep commitments, and to leave no doubts about the credibility of your country's word.

So among my other concerns about the...