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It's a question that President Obama may one day have to answer in earnest: Who would make a better president, his former secretary of state Hillary Clinton or his vice president, Joe Biden?

"Not a chance am I doing this," the president said Thursday when MSNBC's Chris Matthews asked him to compare the two potential 2016 candidates.

"Both Hillary and Joe would make outstanding presidents and possess the qualities that are needed to be outstanding presidents," he said, before praising their work in his administration.

"I think Joe Biden will go down in history as one of the best vice presidents ever. And has been with me, at my side, in every tough decision that I've made from going after bin Laden to dealing with the health care issues to - you name it; he's been there," he said. "Hillary, I think, will go down in history as one of the finest secretaries of state we've ever had, and helped to transition us away from a deep hole that we were in when I first came into office around the world, and to rebuild confidence and trust in the United States."

"They've got different strengths, but both of them would be outstanding."