WASHINGTON DC –  Embattled U.N. envoy Susan Rice is dropping out of the running to be the next secretary of state after months of criticism over her Benghazi comments, she told NBC News on Thursday.

“If nominated, I am now convinced that the confirmation process would be lengthy, disruptive and costly – to you and to our most pressing national and international priorities,” Rice wrote in a letter to President Obama, saying she’s saddened by the partisan politics surrounding her prospects.

“That trade-off is simply not worth it to our country…Therefore, I respectfully request that you no longer consider my candidacy at this time,” she wrote in the letter obtained by NBC News.

Rice had been viewed as one of the front-runners to replace Hillary Clinton as the nation’s top foreign policy official.  (more)

ANDREA MITCHELL: I think this had become sort of an impossible challenge for her to be confirmed, that she realized that, the White House realized it as well. I think they know they are on good political solid ground, as you were just pointing out. This is not going to help Republicans at all, the fact that a woman and a woman of color has been forced out of a confirmation process even before she was nominated.