"He's a likable guy," Johnson said of the former Democratic vice president.
A spokeswoman for Democratic Gov. Tony Evers on Saturday alleged sexism is the reason why communication between Evers and legislative leaders is lacking. Republicans firmly refuted the accusation.
The appearance of a Supreme Court justice or justice-elect at a political party convention is unusual.
The postmortem found the state party was "recklessly reliant" on political consultants, who raked in more than $500,000.
A post-election review the state party conducted concludes the party lost touch with its grassroots supporters, took a top-down approach and was far too reliant on outside consultants and elaborate advertising.
Republican leaders appear to be split over how to use the newfound one-time revenue.
The court's eventual ruling in the case, which takes issue with how GOP legislators convened in December to pass the controversial legislation, will have significant implications for the balance of power in state government.
Evers chose Milwaukee native Joaquin Altoro as executive director of the Wisconsin Housing and Economic Development Authority, one of the last major state agencies or authorities for which Evers' had not appointed a leader.
The announcement of the bipartisan committee comes as Assembly Republicans prepare to vote on Wednesday on a slate of contentious abortion bills.