Roy Beck puts our LEGAL immigration situation into very clear perspective in this video. Many folks, particularly on the left, have repeatedly proposed drastically increasing our legal immigration levels into the United States in order to combat world poverty. Mr. Beck clearly shows why this will not work.
That is not to say that our immigration laws don't need a massive overhaul and changes made to allow a sustainable and beneficial level of immigrants to legally come to the United States. In the long run, this needs to benefit America though, as it ultimately will do nothing to help the impoverished nations of the world.