Obama Names National Security Team

Gates said he was "mindful that we are engaged in two wars and face other serious challenges at home and around the world."

"I must do my duty as they do theirs," he said of the men and women in uniform in Iraq, Afghanistan and elsewhere. "How could I do otherwise?"

He said he was "honored to serve President-elect Obama."

Gates' appointment fulfilled a campaign promise by Obama, the naming of a Republican to his Cabinet.

Holder vowed to revitalize a Justice Department staggered by scandal during the Bush administration, both over the dismissal of federal prosecutors and the administration's program of wiretapping as part of its war against terrorists.

Napolitano, like Clinton, must resign her current job. As a border state governor, she has experience with immigration issues, one of the pressing concerns that will confront the new administration.

Obama said Jones, his national security adviser, "will bring to the job the dual experience of serving in uniform and as a diplomat. He has commanded a platoon in battle, served as supreme allied commander in a time of war and worked on behalf of peace in the Middle East."

The event was unlike those of last week, when Obama was the only one to speak. This time, he called on each of his appointees to make remarks, beginning with Clinton.

Vice President-elect Joe Biden said each member of the team shares the goals and the principles of the new administration that "strength and wisdom must go hand in hand," and that America's security "is not a partisan issue."

Obama has settled on additional members of his Cabinet, although they have not yet been announced.

Among them are former Senate Democratic leader Tom Daschle to be his secretary of health and human services and New Mexico Gov. Bill Richardson to be commerce secretary.