Project BlueBook
The classic investigate and discredit tactic, where they promised to thoroughly investigate UFO sightings, only to dismiss nearly every sighting, leaving trivial room open for ‘legitimate’ Unidentified Flying Object (ie: you saw a weather balloon, but we can’t prove it) unsolved cases, crafted in such a way as to make it look like they gave an honest look at everything, and could easily never discuss such things again.