A recent union drive at an Amazon warehouse on Staten Island didn’t just deliver the first labor victory anywhere in the online retailer’s US operations when workers voted to unionize there. The bitter fight over the unionization effort has also provided a rare glimpse into how Democrats’ consulting class simultaneously advises — and profits off — purportedly pro-union Democratic politicians, corporate union busters, and the labor movement itself.

The prominent Democratic consulting firm Global Strategy Group (GSG) was recently exposed for helping spearhead Amazon’s attempt to crush the Staten Island union drive. It turns out that the firm — which reaps millions of dollars each election cycle conducting polling, research, and public relations for candidates and liberal organizations — has also long done work for some of the country’s largest unions.

GSG originally sought to defend its work for Amazon, claiming in a since-deleted statement that a report from CNBC “incorrectly attributes anti-union work to GSG that was done by others.” On Monday, the firm issued a half-hearted apology, writing: “While there have been factual inaccuracies in recent reports about our work for Amazon, being involved in any way was a mistake. We are deeply sorry, and we have resigned that work.”