they sure did a good job of keeping wraps on some high tech weapons system developments though.
Don't think confuse politicians with the "real" government.
Kinda-sorta. An open government like ours is pretty bad at keeping secrets. It's inevitable that people not playing for the same team get into positions to pilfer highly confidential data, like the stuff that magically disappeared from Los Alamos not that many years ago. We're the same country that announced we had stealth attack aircraft way before we ever actually used them.
Now, if a UFO crashed in North Korea, a cover-up could work. Here? Doubt it.