Setting the stage for a three-way war if a writers' strike occurs next month, the head of the International Alliance of Theatrical Stage Employees (IATSE) said Thursday that he'll sue the Writers Guild of America (WGA) -- which he called a "house of hate" -- if it follows through with its announced plan to bar members from working on animated features should a strike be called. IATSE regards animation production as its turf. But WGA East President Michael Winship observed that "honoring picket lines is a fundamental trade union principle." Jurisdictional disputes between IATSE and the WGA have been commonplace for years, particularly in recent times over reality shows, and it is unlikely that the two unions would show a united front against producers if the WGA does indeed go out on strike.