The unions need to compile a list of bad actor companies that are public. This company list should include large GOP donors, ALEC members, Chamber of Congress members, and other companies with anti middle class agendas. Find companies that donate to anti union congressmen and other causes that are destroying the fabric of our nation. Once this list is compiled it will be easy to cross reference what mutual fund, hedge fund, or brokerage firm own shares in these companies.
Once this list is established the Union needs to sit down with the Goldman Sachs and other money managers and explain to them they intent to yank every penny out of that firm if they are invested in any of these names. The Unions control trillions of dollars in their pension plans. Imagine giving Goldman Sachs three days to divest in all these companies or write you a check for a trillion dollars.