Senator, astronaut, Marine—John Glenn's many achievements have distinguished him as a great American leader. He became a Marine following the attack on Pearl Harbor and proved himself a highly skilled combat pilot in WWII and the Korean War.
Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They're aggressive on the attack and tenacious on the defense. They've got really short hair and always go for the throat.