Carter, in a speech at his former high school, said the military has to attract about 250,000 people a year just to keep up with those who retire or leave the service to pursue jobs, education and other opportunities in the civilian world.

At the same time, only about a third of the 21 million Americans age 17 to 21 are eligible to join the military, with half unable to pass the entry examination and the rest ineligible because they are unable to meet the physical fitness or character standards, he said.

He urged young people to consider joining the military noting that while the sacrifices were real, there were great opportunities as well, including up to $284,000 through the GI bill to help pay for college.

"No one should gloss over the hardships and danger," Carter said, "but I do want you to understand how fulfilling and rewarding military life can be."