In Florida, it is a third degree felony, have no idea in SD.
Its supposed to a felony in any state. What we need is a simple $15k fine for each individual caught. Half of the money goes to the law enforcement agency who arrested the guy, and half to the folks who found the instance of dual voting. Instead of speed traps, we'd have voting traps...and we'd actually see people arrested in their driveway...and toted off to jail