The notion of any government telling the truth, the whole truth and nothing but the truth is quaint in its optimism.
However, those who believe that there are alien beings who have visited our Earth and even partaken of our Burger King believe that the truth is (somewhere) out there.
Clearly, it might cause panic in streets and palpitations in hearts if the US president suddenly stood up and announced that half the Senate was from the Planet Plim. For myself, it would cause no surprise at all, other than to wonder whether everyone on that planet lived alone, married themselves and self-cannibalized late in life.
Still, outgoing White House senior adviser John Podesta is sad that the government hasn't told us what it really knows about UFOs.