I have personally witnessed a method used to reduce the number of inner city voters. Republicans (I recognized one from Summit, NJ operating in Jersey City) with a stern, official look about them, well dressed, and usually in pairs or trios, will casually position themselves about two blocks from polling places at high traffic periods, like 6 or 7 PM. They will act helpful as they inform passersby heading in the direction of the polling place that there are 'sheriffs officers' there, checking for any old unpaid traffic tickets or other 'legal papers'. This is often enough to frighten away perfectly legit voters who don't want any "trouble'. The thing is, these Republican activists are not obviously breaking any laws, as long as they stay a specified distance away from the voting place. Intent is difficult to prove.