Roswell NM, July 2008: After years of speculation the US government has finally admitted that the "X Files got it right", extraterrestrials or aliens have indeed arrived on Earth.
Since July 1947 when the first alien spacecraft crashed in New Mexico the secret has been closely held by only a few high ranking government officials, namely the President, Vice President and Secretary of Defense (formerly War). The information could never be leaked by members of the House or Senate, as it was secured in the same manner as the Nuclear weapons launch codes are today.
These aliens are from a "galaxy far far away" that has had a terrible history of insurrection and revolution. During the initial contact in 1947, the pioneer aliens made it clear that many more of them would be arriving in years to come. These aliens did not want to be conspicuous amongst Earthlings, so as to be able to study our culture unobserved. Employing advanced alien surgical techniques, the arriving aliens were made to look like humans and cleverly disguised as Mexicans. In the 1950's no one would notice a few more Mexicans on this side of the Rio Grande River!
The increasing number of sightings of Unidentified Flying Objects (UFO) in the latter part of the 20th century, combined with the now noticeably large number of Mexican illegal immigrants has made it impossible to keep the secret anymore.