Illegal Immigration and the Law of Unintended Consequences

"This is also a good example of the frequent disconnect between scientists and politicians. Politics lends itself to simple emotionally appealing answers, while reality does not. Following simplistic and emotionally motivated actions runs a high risk of unintended consequences, such as the 'backfire effect' described by Massey and Pren."

It is a good rule of thumb that everything is more complicated than you might originally think.