Glenn Hubbard, dean and professor at the Columbia Business School, explains the thesis of his book "BALANCE: The Economics of Great Powers from Ancient Rome to Modern America," co-authored with Tim Kane of the Hudson Institute, and why the U.S. must cut its debt to avoid the fate of previous "empires." Hubbard speaks with Bloomberg's Kathleen Hays and Vonnie Quinn on Bloomberg Radio's "The Hays Advantage."

Click here to listen to the interview with Glenn Hubbard on The Hays Advantage/Bloomberg Radio