Breaking the law. Just imagine the GOP outrage if Shirley Abrahamson was a featured speaker at, say, a La Crosse County Democratic Party fete

Source:  Barron County Republicans (arrows added)

O'Keefe is a Scott Walker fanboy, Duffy is a GOP Congressman and Quinn a GOP Assemblyman.

From SCR 60.06 A judge or judicial candidate shall refrain from inappropriate political activity.  (Wisconsin State Statutes, with emphasis added)

Related reading: 
Gableman, Club for Growth Leader to Speak at GOP Fundraiser.  (Wisconsin Democracy Campaign, 2/28/2017)