Based on last year’s Military Court of Appeals decision, this might apply to some senior retired military officers and to retired officers who have not yet attained 30 years of active and inactive military tenure. If you retire at 20 years of service, you are held on retainer by way of your retired pay up until the point at which you reach 30 years of total service. After 30 years, you are placed in permanent retired status and no longer subject to UCMJ. Most of the retired generals have passed that 30 years of service. To be recalled to AD after the 30 year mark, you have to consent to it. During the 1st gulf war, there were many officers and senior NCOs who had passed 30 years and who were asked to return temporarily to AD due to their previous job skills. I knew one who was a master chief gunner on battleships. They had brought up the Iowa from mothballs, but had nobody who could teach battleship gunnery to the sailors who were to be assigned to the Iowa. I also knew people who had only been retired a few years who were involuntarily recalled to AD.
As explained to me many many moons ago that Flag Officers can only retire at O8 unless they get special dispensation. It seems these special dispensation has become a rubber stamp.
However, provided what I was told is still true (and it may not be), by re-retiring them at O8 becomes administration rather than court martial and therefore much more difficult to fight.