9. The CIA dosed American citizens with LSD
We are now moving on to the certifiably insane biggest US government cover ups of all times. In the 1950s, the CIA wanted to test the effects of LSD on the mind and whether the drug could be weaponized. The CIA did this by drugging random citizens without informing them and followed up to see what would happen. The tests proved inconclusive, but the appalling lack of ethics was there for everyone to see.