HISTORY LESSONS Defense Secretary Robert M. Gates speaks during North Dakota State University's commencement ceremony in Fargo, N.D., May 14, 2011. "The lessons of history tell us we must not allow our frustrations to cause us to withdraw from the world or diminish our ability or our determination to deal with the threats and challenges on the horizon," Gates said. SHARE: Download: Full Size (0.02 MB) Credit: VIRIN: 204326-A-HZB46-409.jpg Photo Gallery