US senator Tammy Baldwin addressed a letter to Activision Blizzard CEO Bobby Kotick asking him to "negotiate in good faith" with Raven Software workers.
As reported by the Washington Post, Baldwin also sent the letter to Microsoft CEO Satya Nadella.
The senator for Wisconsin, who is a member of the Democratic Party, said she's been following Raven's efforts to unionise, and is "disturbed" by reports pointing to management's attempts to "disrupt" unionisation at the studio.
"I urge you and the management at Raven Software to negotiate in good faith with the workers and suspend any efforts to undermine your employees' legal right to form a union and collectively bargain," Baldwin wrote to Kotick.
She added that she is "troubled" by the recent reports of structural changes at Raven in the wake of the studio's unionisation efforts, which could jeopardise the formation of the Game Workers Alliance union.
She described the studio's reorganisation as a potential attempt "to frustrate efforts by the testers to form a bargaining unit comprised only of quality assurance testers," as the latter will be embedded within each department going forward, rather than being one standalone group.
The letter was sent off the back of the National Labor Relations Board hearing that saw Raven workers face Activision Blizzard management to discuss who should get to vote on the union's formation. The Game Workers Alliance wants the union to represent Raven's QA department, while Activision is pushing for the vote to include the entire studio. The union needs over 50% of the votes to be officially formed, with the chances of it happening lowering if more staff is included.
In December, Activision announced it was laying off a third of the QA team at Wisconsin-based Raven Software. The studio organised a walkout in protest of the redundancies, and quickly established a strike fund and started a campaign to sign union cards.
At the time, Activision Blizzard asked employees not to sign said union cards, and to consider the "consequences" if they did so.
In January, as the Raven strike entered its third week, staff said Activision leadership had not been in touch regarding their demands. Management replied publicly to deny it and said it had been speaking to employees.
However, the company insisted in a SEC filing a couple of weeks later that it wasn't aware of any ongoing labour strikes within its ranks.
Soon after, Raven Software's QA workers voted to unionise and ended their strike. This is when the structural changes at Raven were announced, with Activision Blizzard not recognising the Game Workers Alliance as a union.