I’m a Marine veteran. A recently retired Marine shouldn’t be defense secretary.

I humbly and respectfully disagree. I would say this policy in the past has merit. However, we have had so many D.S. in recent administrations with no combat experience. These are dangerous individuals that have never seen 1st hand combat and the human cost associated. Similar to many of the Secretary of States who so easily have wielded power over military policy and engagement with no understanding of WAR! The sad truth is the many recent administrations are arm chair military policy desk jockeys with (AGAIN my HUMBLE option) NO RIGHT to the positions and power given by POTUS!

A three year wait seems about right, much more so than seven. The best reason the appoint a retired General as SecDef is their connection to the services. The longer the gap between retiring and appointment, the less connected they are to what is currently happening in the Department. Their knowledge isn't degraded over time, but the longer they are away their advantages over non Generals diminish. I don't want them to role right into the job immediately after retiring, but three years seems sufficient.