Michael Moore isn't the only liberal who adopts a pro-union facade in public but hypocritically refuses to work with the over-paid racketeers in private business practices. An employer even larger than Michael Moore is now shunning unions: New York City.
Unions' share in city construction has dropped from over 85% to about 60% in recent years. And, taking a cue from Wisconsin's curbing of public unions, New York companies are "demanding large concessions" from unions and negotiating for "a 25 percent cut in labor costs, by reducing benefits and changing some work rules."
Liberal New York can't be accused of partisan animosity against unions. The Big Apple demonstrates that the turn against unions (public and private) is founded upon economics, not politics. Companies are becoming less and less willing to pay 30% higher costs simply to appease union bosses - at a certain point, the bad publicity and bad blood threatened by turning one's back on unions is still good business.
Unions have a window of opportunity to preserve their relevancy, or I expect this trend of disinvestiture to continue.