Here is the President of the AFL-CIO Rich Trumka's logical reason. And we both know unions aren't political. They are just looking out for the small people. Here's what it's all about IMHO: "...The AFL-CIO is for a fair path toward legalization for all undocumented workers who are working to realize the American Dream. We are for the DREAM Act ...And we need to make sure every worker in America – documented or undocumented – is protected by our labor laws. That is why it is so urgent that we reform our immigration system...so when we talk about making the American Dream real, the labor movement stands for making it real for all of us who do the work of our country...The people doing the hardest work for the least money have no legal protections, no ability to send their children to college, no real right to form a union , no economic or legal security—no way to turn their contributions—their years of hard work—into the most fundamental right of all, the right to vote . That is intolerable for a democracy."

The Dream Act is their plan.

http://www.aflcio.org/mediacenter/prsptm/sp06182010.cfm