I know very little about area 51, so I cannot say anything about it other than that it is very likely, that there would be more of a reaction if there was any unimpeachable proof for any of the supposed alien lifeforms to be found there. I learned that several pictures turned out to be clumsy fakes.
There are many good reasons bare of any alien involvement that could make the government isolate a place like area 51. They might well be developing more lethal weapons there which the public might not like. Right now there are many places the government wouldn't want people to learn about. Places where supposed terrorists are kept without indictment, where such people are tortured! Abu Ghoraib and Guantanamo are but the tip of the iceberg. Mankind seems scarier to me than any Alien race one might envision.
Personally, while I take it more likely than not that there is life out there somewhere I also take it for almost certain that none of the supposed contacts with aliens we allegedly had so far did in fact happen.
Have you seen The Day After Tomorrow? The Vice President is such a dumb***.
That guy was clearly modeled to resemble Dick Cheney. Not only his outward appearance was similar but certainly his stand on so crucial an agreement as the Kyoto protocol was. The politicians in movies are often not nearly as stupid or deceitful as their counterparts in real life.
