“Secret” clearances are fairly universal in the USN. Even USPS carries “Secret” snailmail.
‘Curious where that NSGA was located.
As to difficulty, my USN Dad was strafing, bombing, depth-charging and torpedoing the Japanese in the SW Pacific as an officer.
I was a mere enlistee, whose many addresses and personal referrals were questioned, then even THEIR neighbors were checked!
Odd that Trump is chastised for his bone-spurs deferment by zoned-out tokers; Yet, no one faces more personal danger THAN Trump.