"Unless we are giving opportunity and a quality education to the young men and women in the United States, then we won't have the right people to be able to make the right decisions about our national security," McRaven said.

McRaven said the US needed to develop a "culture of education" within communities, particularly those where residents think they can't afford it or that their children aren't "smart enough."

"There is a school out there for every man and woman in the United States — I don't care what your educational capacity is, what you think it is," McRaven said. "There is a school that will help you matriculate to the point of getting a degree."

While some former US military leaders have had offered witty one-liners when asked which national security threat keeps them up at night, one former commander had an unconventional answer: "K-12 education."

Retired Adm. William McRaven, a former US Navy SEAL commander and head of US Special Operations Command, said he was "the biggest fan" of the younger generation of Americans and that education in grade school played a broader role in national security.

"When I was chancellor, I would have a lot of town hall meetings, or meetings with our alumni, and that question always came up," McRaven, who was chancellor of the University of Texas System, said at the Aspen Ideas Festival on June 29. "And they would always ask ... 'What's your No. 1 national security issue?'"

"I think my answer always surprised them," he added.

McRaven, who stepped down from overseeing one of the largest US school systems in 2018, said he stood by that thinking.

"It was because I recognized that unless we are giving opportunity and a quality education to the young men and women in the United States, then we won't have the right people to be able to make the right decisions about our national security," McRaven said. "They won't have an understanding of different cultures. They won't have an understand of different ideas. They won't be critical thinkers."

"So we have got to have an education system within the United States that really does teach and educate young men and women to think critically, to look outside their kind of small microcosm because if we don't develop those great folks, then our national security in the long run may be in jeopardy," McRaven added.

McRaven recommended the US develop a "culture of education" within communities, particular those where residents believe they cannot afford an education or where they think their children aren't "smart enough."

"There is a school out there for every man and woman in the United States — I don't care what your educational capacity is, what you think it is," McRaven said. "There is a school that will help you matriculate to the point of getting a degree."

McRaven held numerous leadership positions within the special-operations community during his 37 years in the Navy, including overseeing the successful military raid that killed al-Qaida leader Osama bin Laden in 2011.

His remarks echo those of former Secretary of State Condoleezza Rice, who in 2013 said the "crisis in K-12 education is our greatest national security crisis today."

As a member of a Council on Foreign Relations education task force in 2012, Rice helped develop a report that found "educational failure puts the United States' future economic prosperity, global position, and physical safety at risk."

"Human capital will determine power in the current century, and the failure to produce that capital will undermine America's security," the report said. "Large, undereducated swaths of the population damage the ability of the United States to physically defend itself, protect its secure information, conduct diplomacy, and grow its economy."