As Irene Klotz noted here on Discovery News, a measure before Denver voters, if passed, will establish a commission to study extraterrestrials. What's behind it? The proposal is promoted by a man named Jeff Peckman, a conspiracy theorist who believes that there's plenty of evidence that aliens are visiting Earth—but that it's all being covered up.
Conspiracy theorists typically believe that governments around the world have operated in tight collusion to keep the truth from the people. It would be a remarkable achievement indeed, given the changes in administrations and regimes over the decades. Keeping state secrets is difficult enough, but a conspiracy of this magnitude would involve thousands, or perhaps tens of thousands, of people in a dozen or more countries. There are plenty of (often contradictory) stories from both known and anonymous "former officials," yet not a single person has come forth with hard evidence of extraterrestrials.
Peckman and other UFO conspiracy theorists have a difficult time explaining why, exactly, all the governments of the world are so concerned about the public being aware of aliens, what the purpose of a cover-up would be. Often the claim is that the public "isn't ready to know," that somehow knowledge that aliens have really been abducting people, inserting anal probes in them, and whatever other nefarious goings-on is too upsetting and alarming for people to deal with. If the government revealed what they know about aliens, it would send the public into an alarmed panic, perhaps evoking scenes from films such as War of the Worlds and Independence Day.
This widely-held claim is easily refuted when you realize that many people are already convinced that aliens not only visit Earth on a regular basis, but may even be secretly living among us. According to a CNN poll, "80 percent of Americans think the government is hiding knowledge of the existence of extraterrestrial life forms. About 54 percent believe intelligent life exists outside Earth. Sixty-four percent of the respondents said that aliens have contacted humans, half said they've abducted humans, and 37 percent said they have contacted the U.S. government."
So whether or not aliens really exist and are visiting us, many—perhaps most—people already think they do, and thus the claim that such knowledge is too world-changing to accept is invalidated. No one is screaming or panicking. Why would the world's governments go to such lengths to avoid people having final proof of something most of them already believe?
Furthermore, the idea that life may exist elsewhere in the universe is actually promoted, not discouraged, by the U.S. Government. The discovery of an Earth-like planet, Gliese 581g, made international news in September. Apparently the journal Science also didn't get the conspiracy memo warning them to keep quiet, because just last week they published estimates from two astronomers, Andrew Howard and Geoffrey Marcy, that found "that our galaxy, with its roughly 200 billion stars, has at least 46 billion Earth-size planets, and that's not counting Earth-size planets that orbit farther away from their stars in the habitable zone." This finding was widely reported around the world as well, in stories carrying such titles as "Tens of Billions of Earths."
If UFO conspiracy theorists like Peckman are correct, we would logically expect NASA and other branches of the government to discourage, not promote, the idea that there might be life elsewhere in the universe. Surely if the government cover-up is so powerful that it can keep all the evidence of crashed saucers and alien contact under wraps for decades, someone could send a memo to astronomers asking them not to inform the public about all the Earth-like planets out there.
Then again, that's what they want you to think!