A Vietnam veteran re-enlisted to fight in Iraq and Afghanistan

Don Nicholas joined the military twice. The second time was for a reason soldiers don't often give. His first enlistment began as a Marine in 1971. He spent the war on an aircraft carrier and didn't set foot in South Vietnam until the war was over. He re-enlisted to land a spot as an embassy Marine in Saigon in 1974. He was on the second-to-last American helicopter leaving the city as it fell in 1975. He left active duty in 1978.

In 2004, he came back. The Marines thought he was too old at age 52. But for the Army Reserve, he was just what the doctor ordered. Literally.

"It's really not a fascination with war itself," Sgt. Nicholas, who became a podiatrist in the intervening years, told the Wall Street Journal. "It's more trying to keep people from getting killed. I'm taking the spot of some 19-year-old."

In 2011, he was 59 years old, the oldest of 6,000 troops in the 25th Infantry Division sent to eastern Afghanistan. He tried for years to get back into the military after his service ended. He tried during Desert Storm and again after the attacks of Sept. 11, 2001. It wasn't until the height of the Iraq War that the Army was ready to take a man of his skill and advanced age.

Though "advanced" is a term used only because the Army's average age of enlistees back in 2004 was somewhere between 30 and 35. Nicholas' wife says his return to service actually replenished his youthful vigor.

"He doesn't want the other 19-year-olds to go," Mrs. Nicholas said. But "it makes him 19 again. He finds youth in the military."