How often do cabinet officers leave before the end of a president's second term?
Also how often do they leave between a president's re-election and the mid-term election? The US has had twenty-two elections in which the incumbent president has been returned for another term. So for these administrations, how many of their cabinet officials have served the complete eight years. Similarly, how many of the officers have left between the president's re-election and the mid-term elections. For these questions: 1) I am only considering those Senate-confirmed officials that are cabinet-level by law (e.g. State, Treasury) and not those positions that are "cabinet-level" by whim of a particular administration (CIA director, EPA Administrator); 2) if the President dies and is succeeded by the Vice-President (e.g. Harding-Coolidge), I am treating it as one eight-year administration; 3) for the full-term, if the cabinet officer leaves in the last month or two of the term, I am treating it as serving the full-term; 4) there are two weird situations (McKinley-T. Roosevelt and F.D. Roosevelt-Truman) where the president died after being re-elected, but the VP also got re-elected, treat these as overlapping eight-year terms (1897-1905 for McKinley, 1901-09 for T. Roosevelt, 1933-41, 1937-46, and 1941-49 for F. D. Roosevelt, and 1945-54 for Truman).
If a cabinet secretary keeps their position between 2 presidents do they have to be reconfirmed by the senate?
It depends. Lets take John Kerry for example. He was secretary of state.Scenario 1: Obama resigned, Biden kept him. He would not need to be confirmed even in a full first Biden Term in 2016 - Biden was incumbent so no need to reconfirm his cabinet for the same position as under Obama’s half a term.Scenario 2: HRC had won and picked Kerry for same position. He needs to be confirmed. HRC is a new president.
Have former presidents ever revoked security clearances for ex-officials in the past? If so, what were the reasons?
Yes, and one President that I know of actually had his access level quietly downgraded by DIRNSA.That was after Bert Lance was bragging to his buddies about stuff he was hearing about from his friend the President. One paper actually printed high level codeword material he never should have had access too.After careful consideration, that particular President was not briefed on future matters where he didn’t have the absolute need to know.It seems that more recently (especially after 9/11) former government officials have retained their security clearances in order to advise those persons who replaced them. It is also often continued as an “honorarium” for previous high-level government officials.The practice of letting former government workers retain their access to sensitive information indefinitely should cease immediately unless they are actively involved in security matters that require it.A top secret clearance based on a special background investigation SBI is generally good for 5 years, after which time a fresh SBI is required to maintain that clearance (at least it was when I did investigations for G2/PSI at Ft. Campbell). Your particular job determines the ACCESS level granted after you pass the SBI. Once you leave that job, your access ends until you start another job that requires a particular level of access. The most common TS access granted in the government is TS/SCI (sensitive compartmented information) SI or “Special Intelligence”. Another is TK or “Talent-Keyhole”. There are other compartmentalized monikers out there depending on what is required for your job.I can think of two specific cases where compartmentalization failed miserably, Bradley Manning and Edward Snowden.Anyway, it’s usually not the President who revokes a security clearance of former government officials (although he has the power to do so), it’s the responsibility of whoever issues the approval for access to sensitive information within that particular department.Ironically, the same President referred to at the top of my answer ordered much of the compartmentalization procedures after he found out in his initial briefing that too many people had access to some of the highest top secret information they didn’t need to perform their jobs. Probably the best thing he did during his presidency.