The President has invoked the apparently-permanent “national emergency” resulting from the 9/11 attacks to activate Defense (and, I believe, Homeland Security, for the Coast Guard) Department for unlimited (both in number and duration) recall of retired military service members to active duty (outside of wartime and select roles, recall of retirees is limited in duration and, for officers, sharply limited in number simultaneously recalled.)
There are suggestions in other comments that this addresses the USAF pilot shortage (which the 25/service limit on recalled officers would limit without use of an order tied to war or national emergency), but there is no limitation to that application in the order, which activates and delegates the full unrestrained emergency power to the service secretaries subject to the discretion of the Secretary of Defense.
Without further Presidential action, every single retired member of the Armed Forces could be called up, indefinitely, under the terms of this order.
“His specialty was alfalfa, and he made a good thing out of not growing any. The government paid him well for every bushel of alfalfa he did not grow. The more alfalfa he did not grow, the more money the government gave him, and he spent every penny he didn't earn on new land to increase the amount of alfalfa he did not produce. Major Major's father worked without rest at not growing alfalfa. On long winter evenings he remained indoors and did not mend harness, and he sprang out of bed at the crack of noon every day just to make certain that the chores would not be done. He invested in land wisely and soon was not growing more alfalfa than any other man in the county. Neighbours sought him out for advice on all subjects, for he had made much money and was therefore wise. “As ye sow, so shall ye reap,” he counselled one and all, and everyone said “Amen.”
There are suggestions in other comments that this addresses the USAF pilot shortage (which the 25/service limit on recalled officers would limit without use of an order tied to war or national emergency), but there is no limitation to that application in the order, which activates and delegates the full unrestrained emergency power to the service secretaries subject to the discretion of the Secretary of Defense.
Without further Presidential action, every single retired member of the Armed Forces could be called up, indefinitely, under the terms of this order.