The West Coast locals of the Intl. Alliance of Theatrical Stage Employees are endorsing Rep. Howard Berman (D-Calif.) in his primary race for a San Fernando Valley congressional seat against Rep. Brad Sherman (D-Calif.).

The endorsement is significant because many of the members of the locals — which include studio craftsmen and women like property masters, key grips set designers and costumers — live in the district. The locals represent some 35,000 workers in the Los Angeles area.

Matthew Loeb, IATSE’s international president, said in a statement, “Howard’s record of extraordinary legislative accomplishments on behalf of our members is unparalled. When it comes to protecting jobs and our livelihoods, Howard Berman is a workhorse, not a show horse.”

The locals cited Berman’s championing of labor rights, and noted that he represented unions including IATSE in a previous career as a labor lawyer. They also cited his sponsorship of anti-piracy legislation, including the Stop Online Piracy Act that was introduced this week.

Redistricting is pitting Berman against Sherman in one of the most contentious primary battles of all 2012 House races. Although Sherman has acknowledged that Berman would get the support of the bulk of industry leaders, he has said that his strength will be in prominent Valley leaders, including many outside his district.