(Advisory: please note strong language in paragraph seven)

By Louis Charbonneau and Susan Cornwell

UNITED NATIONS/WASHINGTON (Reuters) - Susan Rice has had a series of diplomatic triumphs as U.S. ambassador to the United Nations. President Barack Obama, an old friend, showed he has her back when last week he publicly challenged her Republican critics over the Benghazi controversy to "go after me" rather than her. She knew former Secretary of State Madeleine Albright from the age of 4.

And yet Rice is now fighting for her political future. Her chances of becoming the next secretary of state - replacing Hillary Clinton - have been significantly damaged.

Senior Republicans, such as Senators John McCain and Lindsey Graham, have said they will oppose her getting the job, signaling a confirmation battle if Obama decides to nominate her. Some critics in the U.S. media, such as Washington Post columnist Dana Milbank, have said she is unsuitable for the position.

The immediate source of a lot of the criticism is her appearances on Sunday morning television shows in September five days after the U.S. ambassador to Libya, Christopher Stevens, and three other Americans had been killed in Benghazi.

Her critics bitterly complain that she misled the American public by suggesting that the assault was the result of a spontaneous protest rather than an organized assault by affiliates of al Qaeda. During the U.S. presidential campaign, supporters of Republican candidate Mitt Romney seized on the issue to attack Obama.

The antipathy in Washington and elsewhere, though, is based on more than a series of TV interviews. While U.N. diplomats and U.S. officials who have dealt with Rice praise the intellect of the 48-year-old former Rhodes scholar and graduate of Stanford and Oxford, they say she has won few popularity contests during her meteoric rise.

Diplomats on the 15-nation U.N. Security Council privately complain of Rice's aggressive negotiating tactics, describing her with terms like "undiplomatic" and "sometimes rather rude." They attributed some blunt language to Rice - "this is crap," "let's kill this" or "this is bullshit."

"She's got a sort of a cowboy-ish attitude," one Western diplomat said. "She has a tendency to treat other countries as mere (U.S.) subsidiaries."

Two other diplomats - all three were male - supported this view.

"She's not easy," said David Rothkopf, the top manager and editor-at-large of Foreign Policy magazine. "I'm not sure I'd want to take her on a picnic with my family, but if the president wants her to be secretary of state, she'll work hard."

Indeed, along with a "no-nonsense" style, Rice has the most important ingredient for a successful secretary of state - a close relationship with the U.S. president, Rothkopf said.

Russian Ambassador Vitaly Churkin, himself not known for mincing words, publicly admonished Rice after she said Russian calls for an investigation into civilian deaths in Libya caused by NATO were a "bogus" ploy.

"Really this Stanford dictionary of expletives must be replaced by something more Victorian, because certainly this is not the language in which we intend to discuss matters with our partners in the Security Council," said Churkin, mocking Rice's education at Stanford.

More immediately at the United Nations, she faces criticism from human rights activists and some diplomats because of U.S. opposition to public criticism of Rwanda for its role in the worsening conflict in the Congo.

BREAKING HER SILENCE

Rice, who declined to comment for this article, broke her silence on the Benghazi controversy on Wednesday, defending her September statements about the attack.

But she did so on Thanksgiving eve when many Americans were traveling and when her comments were likely to be overshadowed by news of a ceasefire between Israel and Hamas.

"I relied solely and squarely on the information provided to me by the intelligence community," Rice told reporters at the United Nations. "I made clear that the information provided to me was preliminary and that our investigations would give us the definitive answers."

While Rice said some statements about her by McCain were "unfounded," she may have been trying to mend fences when she added: "I look forward to having the opportunity at the appropriate time to discuss all of this with him."

People who know Rice say she is finding it hard to keep up her spirits during a long autumn of criticism. "It's not easy being attacked publicly by people who have their facts wrong day after day," one U.S. official said.

Rice's defenders say that a lot of the attacks smacked of sexism as the same tough manner she can display has been seen as an asset in some legendary male American foreign affairs officials.

Rothkopf, who was an official in President Bill Clinton's administration, cited James Baker and Henry Kissinger as exemplary secretaries of state.

They were "tough infighters who broke a few eggs and made some enemies. They are admired for their toughness, and (Rice) is attacked for her abrasiveness," he said.

SOME SAY EMINENTLY QUALIFIED

Certainly, Rice has won some accolades for pushing the U.N. Security Council to adopt new Iran and North Korea sanctions, helping secure the toughest U.N. measures to date against those two countries over their nuclear programs. Rice also played a key role in negotiating last year's war resolution on Libya.

Current and former U.S. officials aligned with the Obama administration say Rice is eminently qualified for the post of secretary of state.

They say the attacks on her during the presidential campaign were part of Republican efforts to frame the Benghazi assault as a terrorist attack, possibly linked to al Qaeda, on Obama's watch.

"The president has a great record in fighting al Qaeda, so (Republicans) try to find a way of attacking his record on al Qaeda," said Richard Clarke, who was Rice's boss when she worked at the U.S. National Security Council during Bill Clinton's first term.

Rice became an official in the Clinton administration in the 1990s, at the National Security Council and State. Then, under Obama, she became the youngest woman and the first black female to become U.S. ambassador to the U.N.

She grew up close to the levers of power. She is the daughter of the late Emmett Rice, who was a Cornell University economics professor and member of the Federal Reserve Board of governors. Albright, who is a family friend, recommended Rice to become assistant secretary of state.

"We often traveled together and I took her advice very seriously," said Albright, who served as U.N. ambassador from 1993 to 1997 and secretary of state from 1997 to 2001. "I think she is one of the smartest people I know in national security issues."

REPAIRED TIES

While some Republicans have accused her of sacrificing U.S. interests in her effort to woo U.N. diplomats and also complain that she is too often absent during U.N. Security Council votes, neither criticism is given much credibility by other diplomats in New York.

They say Rice, whose husband and children live in Washington and who is a member of Obama's Cabinet, has an advantage as a U.N. negotiator because other nations' delegations know that when she takes a position on an issue, the president is almost certainly behind her. Continued...