Ex-Presidents should not be included in the "Daily Briefing" either. Their term is up. They should move on to writing books, building houses, whatever.
"But Joe", you say, "Sometimes Ex-Presidents meet with foreign leaders. Obama met with Merkle just recently".
Why? Obama has no input into US policy: none, nada, zip. His opinion has no more relevance than mine or yours. Carter shouldn't be off trying to negotiate with the NOKs, and we don't need a Bush kowtowing with the Saudis. Part of the problem is the leaders of the EU go whining to Obama when they don't get their way. Too bad. The Trumpster is large and in-charge. Obama served his Constitutionally mandated two term limit. GW did too. There is no reason to give briefings to Clinton, Bush I, or Carter. They have been out of office more than two decades. They have nothing to offer on any current top secret topic. They should not be getting a daily briefing.
Besides, if something does come up, the President is responsible for National Security. He can fill them in on any relevant topic, should he need their advise.
It is time we start cleaning up the swamp. No longer keeping old ousted retired and fired employees in the loop so they can lobby, do the TV circuit, and collect per diems from the teats of the Federal Government is a good place to begin.