On "This Week with George Stephanopoulos" this morning, Sen. Marco Rubio (R-Fla.) discussed Benghazi, the 2016 presidential race and climate change.

Sen. Marco Rubio (R-Fla.) addresses the New Hampshire Rockingham Committee Freed Founder's Dinner in New Castle, N.H. Rubio visited the state as he weighs a 2016 presidential run. (Scott Eisen/Getty Images)


And he was asked about the woman who everyone assumes will be the Democratic nominee in 2016 — former secretary of state Hillary Rodham Clinton.

“I’m sure she’s going to go out bragging about her time in the State Department. She’s also going to have to be held accountable for its failures, whether it’s the failed reset with Russia or the failure in Benghazi that actually cost lives," Rubio said. He gave Clinton an "F" for her tenure in the State Department. Congressional Republicans are set to reinvestigate the Obama administration's response to the September 2012 Benghazi attacks, which Clinton has said were the "biggest regret" of her tenure. The public agrees — a recent Pew Research Center poll shows that Benghazi is considered the top negative of her entire political career.

“If you look at the diplomacy that was pursued in her time in the State Department, it has failed everywhere in the world,” Rubio said. “If she is going to run on her record as secretary of state, she’s also going to have to answer for its massive failures."

ABC's Jonathan Karl interviewed Rubio in New Hampshire on Friday, where he was fundraising for Sen. Kelly Ayotte (R-N.H.) and speaking to the local media. It was Rubio's first trip to the early presidential primary state in two years, which, of course, fueled speculation about his future political ambitions.

Karl asked Rubio whether he thought he were ready to be president. He quickly responded with an “I do" but followed that even more quickly with a "but."

"I think that’s true for multiple other people that would want to run," Rubio said. "I mean, I’ll be 43 this month, but the other thing that perhaps people don’t realize — I’ve served now in public office for the better part of 14 years. Most importantly, I think a president has to have a clear vision of where the country needs to go and clear ideas about how to get it there, and I think we’re very blessed in our party to have a number of people that fit that criteria.”

If he runs for the White House in 2016, he said, he will not run for reelection in his Senate seat. “I believe that if you want to be president of the United States, you run for president. You don’t run for president with some eject button in the cockpit that allows you to go on an exit ramp if it doesn’t work out,” he said.

During the interview, Rubio also discussed the environment. The senator is skeptical that addressing climate change would do anything to alter our current environmental circumstances.

"I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it," he said. "And I do not believe that the laws that they propose we pass will do anything about it, except it will destroy our economy."

In a New York Times article published last week, Rubio declined to answer questions about climate change. In the story, a University of Miami political scientist offered his read on Rubio's silence.

“Jeb likes to take positions on hot-button issues, the same with Rubio," he said, referring to former Florida governor Jeb Bush (R). "On immigration they are further mainstream on that than the rest of the G.O.P. But on this, Republicans are dead set against taking action on climate change on the national level. If you have political aspirations, this is not something you should talk about if you want to win a Republican primary.”