The U.N. ambassador will not require Senate confirmation for the new post.
Rice has been a key focus in the ongoing controversy surrounding the fatal attacks on the U.S. consulate in Benghazi, Libya, because of accounts she gave on several Sunday morning talk shows that later proved to be inaccurate.
But the president had nothing but high accolades for her. Speaking from the White House Rose Garden, he praised her for being pragmatic, fearless and tough.
"She's helped to put in place tough sanctions on Iran and North Korea. She has defended Israel. She has stood up for innocent civilians from Libya to Cote d'Ivoire. She's supported an independent South Sudan. She has raised her voice for human rights, including women's rights," Obama said. "Put simply, Susan exemplifies the finest tradition of American diplomacy and leadership."
Earlier this year, Rice was considered to be a top contender to become secretary of state in the president's second term, but withdrew herself from consideration because of harsh criticism from congressional Republicans over her Benghazi comments.
"Sen. John McCain, who played a significant role in a campaign to block her potential State Department nomination, said in a tweet that he disapproves of Rice's new appointment but "would make every effort" to work with her on important issues.
"He doesn't really have much of a choice," said George Mason University professor Michael Fauntroy, because the national security adviser position does not require Senate confirmation.
"He can't keep her from being national security adviser, and some of these Republicans are going have to careful about how many rocks they're prepared to throw at Rice," Fauntroy added.
The administration is confronting several challenges on the national security front, including the ongoing situation in Syria, "which is of grave concern to many of us in Congress," Rep. Karen Bass, a member of the House Foreign Affairs Committee, told BET.com.
Bass said she's also closely monitoring the increase of al-Qaeda-affiliated and other extremist groups on the African continent, particularly in Mali, Boko Haram, Nigeria and the Democratic Republic of the Congo.
"I think Ambassador Rice is well-suited for these areas, particularly given her previous service on the National Security Council and as an assistant secretary of state for African Affairs," added Bass, who applauded the appointment.
Robert Smith, a San Francisco State University political scientist, called the appointment, given Republican efforts to discredit Rice, as well as the judicial nominations announced Tuesday a "politically courageous move" by Obama.
"For him to do that essentially says to them, 'I'm going to manage my own household whether you like it or not,'" Smith said.
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