The Mercatus Center reports that unions give more money to politicians than corporations (the chart down below looks at the top 25 donors). You'll notice that Comrade Bernie Sanders , Hillary Clinton, and Barack Obama are shy about these important facts. After all, the big donors are looking to get "something" from the political system. Just a reminder the next time a leftist wants to talk to you about Citizens United. It appears the overpaid government workers at AFSME give more money to politicians than Microsoft , the American Bankers Association , and Citgroup.