A domestic, internal army for America? Who would be the target?

MRAP
Coming to a street in your hometown?

Illegal aliens? Invading Canadians? Rampaging Boy Scouts or Tea Partiers? It’s anyone’s guess, but it has been widely reported that the federal government’s Department of Homeland Security (DHS) has stockpiled 1.6 billion rounds of .40 caliber and 9mm ammunition over the past year. Now the news comes out that the DHS has purchased 2,700 military-style MRAP (Mine Resistant Ambush-Protected) vehicles…for use on the public streets of America (Read about it at Gateway Pundit HERE.) If this has been confirmed and is true, I have a question: Is America in need of  a large internal military force? If so, why?