HILTON HEAD, S.C. --  Appearing on stage with Mitt Romney for the first time since endorsing him for president, former UN Ambassador John Bolton on Friday night unleashed a scathing indictment of President Barack Obama, whom he said "doesn't care" about national security in the same way other presidents had before him.

"He’s not only the most radical president in history domestically, he is the first president, Republican or Democrat, at least since Franklin Roosevelt, who didn’t get up every morning thinking first about what threats the United States faces," Bolton said. "He just doesn’t care about national security the way other presidents did. He’s much more interested in moving us toward a social Democratic health care system, a social Democratic automobile manufacturing system, a social Democratic environment, you get the picture." 

Romney campaign officials did not immediately respond when asked if the former Massachusetts governor agreed with that assessment.

Bolton also trivialized the biggest national security event to have taken place during Obama's administration, the raid that killed Osama bin Laden last May, saying Obama did not deserve credit for the successful mission.

"You know the irony is he’s campaigning on the basis that he’s a success as a foreign policy president," Bolton said. "It’s just really amazing and you ask, What is it that made the success? And it’s because Navy SEAL Team Six killed Osama bin Laden. That’s his definition of success. As somebody pointed out, in 1969 when Americans landed on the moon, it’s like Richard Nixon taking for credit for that, because it happened to occur during his presidency."

Romney himself told Fox News in December that "any president" would have signed the order to take out bin Laden, a statement he later expanded upon in an interview with NBC's Chuck Todd, giving Obama some credit for being the person to ultimately have done so.

"I give credit to this president for actually having made the decision. I don't think it's unusual on the part of this president to have finally taken out Osama bin laden," Romney said. "After all, we had been looking for him for some time. Intelligence finally gave him a good indication of where he was. He gave the order. I do think prior presidents would have done the same thing had they been in the same position."

At Romney's campaign event here tonight, a forum for veterans, with a national security focus, Bolton also said Obama was a "failure across the board" on foreign policy and had hurt America's interests abroad, along with those of our allies.

"This president has done almost everything possible to weaken the United States, to jeopardize our interests and our friends around the world," Bolton said.

Bolton is a controversial former U.S. ambassador to the United Nations and undersecretary of state for arms control under George W. Bush. He had been back in the news recently after former House Speaker Newt Gingrich said in December that, if elected president, he would ask the prominent neoconservative to be his secretary of state. 

But Bolton endorsed Romney on Wednesday night, an event a senior Romney adviser told NBC News that the campaign hoped would be a signal to undecided Republicans that Romney was the strongest candidate in the field on the subject of foreign policy. Friday night, in explaining his decision to endorse, Bolton praised Romney as the "one person in the race today" whom voters could count on to protect the American people.