Hagel is a term that can refer to various subjects, but it is most commonly associated with Chuck Hagel, an American politician and former U.S. Secretary of Defense. He served in this role from 2013 to 2015 under President Barack Obama. Before his political career, Hagel was a decorated Vietnam War veteran and a U.S. Senator from Nebraska. In addition to his political achievements, Hagel has been involved in various international relations and defense issues. His tenure as Secretary of Defense focused on military budget reforms, the withdrawal of troops from Iraq, and addressing emerging global threats.