Back in August 2015, when Bernie Sanders and Hillary Clinton were still battling it out for the Democratic nomination and Sanders’s campaign was viewed as a quixotic amusement, Clinton won the pivotal endorsement of the International Association of Machinists and Aerospace Workers (IAM), one of the nation’s biggest unions. It was the second endorsement Clinton had secured from a national union and helped shore up Clinton’s credentials as a friend to workers.

Emails released by WikiLeaks over the past two weeks suggest the kind of machinations that went on behind the scenes to secure Clinton that endorsement. According to a July 8, 2015 email from Nikki Budzinski, the Clinton campaign’s labor outreach director, the union’s then international president, Tom Buffenbarger, moved up the endorsement vote many months and did so without the knowledge of most of IAM’s officers.

“I just spoke with IAM, they have confidentiality [sic] shared with us that Buffenbarger will be moving his board to take a endorsement vote on August 14th in NYC,” wrote Budzinski. “Only three officers at IAM are aware of this, so its [sic] being tightly held so that they don’t have any issues on the board with timing.”