(The Root) -- The tragedy in Benghazi, Libya, has already claimed the lives of four Americans, as well as the career of one American diplomat. The first African-American female ambassador to the United Nations, Susan Rice, saw her hopes to succeed Hillary Clinton as secretary of state, and her reputation, go up in flames after sustained conservative criticism of her response to the Benghazi assault. There were those who believed that she would not be the final casualty.

As secretary of state, Clinton has claimed ultimate responsibility for the fallout from the incident. In doing so, she raised questions about the long-term impact of the tragedy on the Department of State as well as on her legacy, which includes a possible presidential run. The idea that Benghazi could ultimately prove fatal to her presidential hopes gained such traction that when Clinton recently battled health woes, thus delaying her testimony on the matter, conservatives insinuated a cover-up.

Former Florida Republican Rep. Allen West accused her of having "Benghazi flu," while the Fox News Channel's Charles Krauthammer accused her of having "acute Benghazi allergy." They were, of course, proved wrong -- embarrassingly so -- when Clinton's doctors confirmed that she had been suffering from a blood clot near her brain. It is likely because of these debunked accusations that so many elected officials, including conservative ones, spent so much time expressing relief for her recovery during her testimony on Benghazi before the House and Senate on Wednesday.

But besides conservatives' best attempts to make up for the insensitive and insulting allegations of some of their comrades, it appears that some of them had another goal: to stop the Clinton presidential train before it pulls out of the station. Despite their best efforts, it didn't work.

The secretary of state's most heated exchanges of the day were with certain Republicans -- Sen. John McCain of Arizona, Sen. Rand Paul of Kentucky and Sen. Ron Johnson of Wisconsin. Paul and Johnson are Tea Party darlings who clearly were on a mission to get the better of Clinton.

Paul, rumored to be a possible 2016 presidential opponent of Clinton's, should she run, fired off perhaps the most memorable line of the day when he told her that had he been president, he would "have relieved you of your post" for her handling of the affair. The line is memorable for its confrontational tone as well as its employment of fantasy. No one, including most Republicans, remotely believes in the possibility of a Paul presidency.

In her testy exchange with Sen. Johnson, Clinton showed more emotion than Americans are used to seeing from her -- even those Americans who recall the days when she endured the scandal of her husband's affair and impeachment. Under Johnson's aggressive questioning of the timeline of information gathering in the days immediately following the Benghazi tragedy, the secretary of state displayed anger and exasperation, saying, "With all due respect, the fact is we had four dead Americans. Was it because of a protest or was it because of guys out for a walk last night who decided to kill some Americans? What difference at this point does it make? It is our job to figure out what happened and do everything we can to prevent it from ever happening again, Senator."

Though Johnson later referred to the remarks as "theatrics," at the time of the exchange he seemed caught off guard by her emotion.

And then there was Clinton's exchange with her alleged friend and former colleague, Sen. John McCain, who said he did not believe aspects of her testimony. He went on to speak for several minutes, almost as though he were testifying. Clinton calmly told him that they simply disagreed.

McCain's demeanor at the hearing will likely only further solidify his reputation as one of the sorest losers in American presidential history. (Shortly after McCain's cantankerous questioning of the secretary, Democratic Sen. Dick Durbin of Illinois pointedly referenced how the Senate was previously indisputably misled regarding weapons of mass destruction, thus resulting in a costly and casualty-laden war -- the insinuation being that McCain and others didn't press that matter the way they've pressed Benghazi.)

Clinton's ability to handle the Benghazi hearings and, more important, to handle the men attempting to manhandle her in their questioning confirmed that she is more than ready to handle yet another rough-and-tumble presidential campaign, as well as the job of president.

But perhaps an even more important development to come out of her testimony is that for those critics who dared presume that her health woes raised questions about her toughness, she showed just how tough she really is. 

Keli Goff is The Root's special correspondent. Follow her on Twitter.

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