(CNN) In 2006, Obama voted against raising the U.S. debt ceiling. But now, he's asking Congress to do just the opposite. Since March 1962, the debt ceiling has been raised 74 times, according to the Congressional Research Service. Ten of those times have occurred since 2001. White House press secretary Jay Carney said failing to raise the ceiling would be "Armageddon-like in terms of the economy." Should the debt ceiling be raised or not? CNN's American Morning speaks with Harvard economics professor Kenneth Rogoff about the intricacies of doing so.