Voting machine integrity cannot be taken for granted in Wisconsin. The computerized aspects of vote tabulation have been privatized. In many and perhaps most counties in Wisconsin, the tabulation signals go through programs owned and controlled by corporations for profit. These programs can be hacked without leaving a trace. Even paper ballots are not much protection against fraud because clerks do not and will not hand count their paper ballots before certifying an election.
Please note that this does not call into question the honesty of county or municipal clerks across Wisconsin, who (with one notable exception prominent in the 2011 Supreme Court race) appear to perform their election duties professionally. It is the electronics of vote counting that pose a grave danger for the November, 2012 election. Currently hand counting of ballots of the 2012 Governor Recall Election is underway. Please consider volunteering for this effort at Wisconsin Wave.