All you need to produce is physical evidence. Some DNA would be best. Do ETs eat, drink, or have diseases? Can they die? Just like those that think Big Foot exists, why is there no DNA from the hair since they are so hairy? No skeletons exist. Even waste products would be useful. Do aliens poop?Why should the government admit to things that do no exist?"My view is that if there is no evidence for it, then forget about it. An agnostic is somebody who doesn’t believe in something until there is evidence for it, so I’m agnostic."— Carl Sagan