President Barack Obama on Monday nominated former Republican Senator Chuck Hagel to be his new secretary of defense. Obama also chose counterterrorism adviser John Brennan to head the CIA.
Obama made his choices official in the White House East Room with Hagel and Brennan standing by his side.
The president noted that Hagel, a Vietnam War veteran, would be the first person of enlisted military rank to serve as secretary of defense.
"He understands that sending young Americans to fight, bleed in the dirt and mud, that is something that we only do when it is absolutely necessary. My frame of reference, he has said, is geared toward the guy at the bottom who is doing the fighting and the dying," he said.
Hagel served two terms as a senator from the Midwestern state of Nebraska. He gained a reputation as someone who is willing to break with his own party on key issues.
Hagel paid tribute to departing Defense Secretary Leon Panetta and members of the armed forces.
"I am also grateful for an opportunity to help continue to strengthen our country and strengthen our country's alliances and advance global freedom, decency and humanity, as we help build a better world for all mankind," he said.
Hagel has faced sharp criticism from some Republican senators, and pro-Israel groups, who say he has shown hostility toward Israel and weakness on how to deal with Iran.
Senate minority leader, Republican Mitch McConnell spoke Sunday on NBC television's "Meet the Press" program.
"I think there will be a lot of tough questions of Senator Hagel. But he will be treated fairly by Republicans in the Senate," he said.
Texas Republican Senator Ted Cruz appeared on the "Fox News Sunday" program.
"Hagel's record is very, very troubling on the nation of Israel. He has not been a friend to Israel. And in my view, the United States should stand unshakably with the nation of Israel," he said.
White House Press Secretary Jay Carney defended Hagel on Monday. "Senator Hagel has been a staunch supporter of Israel, of the Israeli-American relationship, of U.S. support for Israel's security throughout his career," he said.
Hagel also faced criticism from organizations representing homosexuals, and issued an apology in December for a comment in 1998 that disparaged a gay U.S. diplomat.
John Brennan's nomination to head the Central Intelligence Agency is expected to be less controversial, although he will face tough questions about the Obama administration's counterterrorism policy.
He has been the administration's key spokesman on the use of drones in targeted killings of suspected terrorists, calling them "legal, ethical, wise and highly effective."
"If confirmed as director, I will make it my mission to ensure that the CIA has the tools it needs to keep our nation safe, and that its work always reflects the liberties, the freedoms and the values that we hold so dear," he said.
Brennan would replace Army General David Petraeus, who resigned in November because of an extramarital affair.
President Obama called Brennan a tireless worker for national security, saying he would bring extensive experience and insights to the job.
"John developed and has overseen our comprehensive counterterrorism strategy - a collaborative effort across the government including intelligence, defense and homeland security, and law enforcement agencies," he said.
Obama said Brennan's work contributed to major successes against al-Qaida that have made it harder to plan attacks against the United States. The president called on the Senate to act as soon as possible on both nominations.