Sen. Bernie Sanders (I-VT) threw his support behind striking YouTube Music workers in a letter addressed to Google CEO Sundar Pichai Tuesday, as first reported by the Austin Chronicle.

Sanders’ support comes amid growing tensions between workers on YouTube Music’s Content Operations team and its parent company, Google. The nearly 60 workers are formally employed by Cognizant, a third-party contractor to Google. Last October, they filed for a union election with the 1,300-member Alphabet Workers Union (AWU). But shortly after that request was filed with the National Labor and Relations Board, Cognizant issued a new return-to-office mandate that organizers — and Sanders — argue amounts to an illegal union-busting strategy.

“We worry that Cognizant suddenly imposed these impossible requirements on these workers in response to them exercising their right to organize a union,” Sanders wrote to Pichai along with Austin Rep. Greg Casar (D) on Tuesday. “Our request to you is simple: Ensure that all Google workers, including YouTube Music workers, are able to freely exercise their right to join a union as guaranteed by federal law.”

The YouTube Music workers officially called a strike on February 3rd, three days before the return-to-office mandate went into effect. In a Monday tweet, the AWU called it the first-ever strike at Google. While their employer, Cognizant, is a third-party contractor to Google, the AWU argues that the two companies are joint employers for the YouTube Music Content Operations Department. 

Responding to a request for comment, Google spokesperson Courtenay Mencini said, “The individuals striking today are employees of Cognizant, not Google or YouTube, and we respect their right to join a union or not. Their decision will not affect our work with Cognizant, as we hold many contracts with both unionized and non-union suppliers. As the employer, Cognizant is responsible for these workers’ employment terms.”

In January, Sanders became the chair of the powerful Senate Committee on Health, Education, Labor, and Pensions. In addition to his Tuesday letter to Google, Sanders has leveraged his newfound power to go after other companies allegedly obstructing unionization efforts and running afoul of federal labor law. Earlier this month, Sanders hinted at subpoenaing Starbucks CEO Howard Schultz to testify before his committee about the company’s “egregious union-busting campaign.”

Updated February 21st, 2023 at 2:15PM ET: Included a statement from Google.