A drill sergeant passes a row of recruits -- many of them high school juniors and seniors -- headed into their first day of military life at the Army National Guard complex in Marseilles, Ill. Jeff Roberson/AP hide caption

itoggle caption Jeff Roberson/AP

More American colleges are offering classes that teach students to deal with a shrinking and increasingly dangerous world. iStockphoto.com hide caption

itoggle caption iStockphoto.com