(CNN) -- Susan Rice, the U.S. ambassador to the United Nations who drew heavy criticism from Republicans over her statements after the September attacks on a U.S. diplomatic mission, withdrew her name from consideration for secretary of state on Thursday.
In a letter to President Barack Obama, she said "the confirmation process would be lengthy, disruptive, and costly -- to you and to our most pressing national and international priorities. That trade-off is simply not worth it to our country."
Obama acknowledged her letter in a statement that described her as "an extraordinarily capable, patriotic, and passionate public servant."
Read Rice's letter to the President
She was thought to be a frontrunner for the post, which Secretary of State Hillary Clinton said she would vacate as soon as a successor is confirmed.
But Rice drew criticism for her description of the September 11, 2012, attack on the U.S. mission in Benghazi, Libya, which killed four including the U.S. Ambassador to Libya, Chris Stevens. On several television programs several days after the attack, she described a protest of an anti-Islam video outside the mission buildings.
She said her comments were based on declassified talking points, and sources within the intelligence community said the talking points were not modified by any other body, such as the White House.
Obama had defended her, describing the criticism from several key Republicans as "outrageous." "If Senator McCain and Senator (Lindsey) Graham and others want to go after someone, they should go after me," Obama said at a White House news conference in late November. "When they go after the U.N. ambassador, apparently because they think she's an easy target, then they've got a problem with me."
She visited Capitol Hill in an attempt to answer what the legislators called "unanswered questions," but her visit there appeared to backfire. Senators who sat in on the meetings said her appearances raised more questions than they answered.