[martinflack]

> It basically requires an act of congress or the President to change it once done.

Isn't the mere passage of time also a remover of classification? Like isn't there a default time from the creation date?

Or it must be positively declassified by an action?

[withinboredom]

IIRC, after 50 years it can be reviewed for declassification. I don't think there is anything automated about it.