The fraud is being investigated around the state; the state's attorney in Milwaukee is a "see-no-evil, hear-no-evil, speak-no-evil" Democrat. Odds are low anything will be done. However, if the Republicans in the state legislature develop some cajones, they will reintroduce a bill calling for a voter ID. This idea was passed in the assembly after the vote fraud in 2000, but defeated in the Dem controlled senate.
The only things that mitigates against immediate charges are that he's not up for re-election in his Senate seat until 2004 and they might decide to pull his name off the ballot, knowing that the black voting population is a bunch of lemmings. Still, I'd expect him to be charged by the end of August.