Because they are potential Dem voters. MEXICALI, Mexico (WaPo) — Arrests of illegal migrants trying to cross the southern U.S. border have plummeted to levels not seen since the early 1970s, according to tallies released by the Department of Homeland Security last week, a historic shift that could reshape the debate over immigration reform. The Border … Continue reading Arrests of Illegal Immigrants on U.S.-Mexico Border Plummets Since Obama Took Office, Numbers Not Seen Since Nixon-Era…