Thought experiment.
Bill Clinton in 1999 makes sure a bunch of his buddies are hired to be on the clearance committee or whatever in the CIA or FBI.
Supreme Court rules on the recount, Electoral College votes...
But then the clearance committee of midlevel bureaucrat partisan hacks says..."Wait a minute. Can't give W a clearance because of that drunk driving conviction...Gore is President.
Being President is a hell of a lot different from whatever jobs you had.
That would make sense.
I guess like the requirement that you had to be born in the USA in order to be eligible to run for Prez, you would also need to be able to get clearance.
But it makes sense, I guess that one doesn't need it.