Of course a thread of this nature would not be complete without Dane weighing in.
Your anology to the Berlin wall is apples and oranges. Reagan was talking about freedom for people in their own countries and the time had come for Germany to be reunited. It has nothing to do with illegal immigration and preserving our sovereignty.
Reagan believed in sovereignty, but not in the neo-Khruschev way you and your side promote, building walls.
Also Reagan was the one who first proposed NAFTA.