Discord between the groups first sounded more than two years ago when the Vancouver Musicians' Association independently negotiated a new gig with a local film orchestra because it feared losing work to non-union shops.
The American Federation of Musicians argued the deal was off key because the association didn't have the authority under union bylaws to make the deal, and dismissed the local executive and appointed a trustee.
The association decided to take the matter to court, where it asked a judge to rule the trusteeship a mistake and order the section of bylaw unenforceable.
Justice Carol Ross has decided that the controversial rule is inconsistent with the entire bylaw, setting aside the trusteeship.
The association represents about 2,000 musicians who have negotiated deals with operas, symphonies and theatres, and the federation has about 240 locals across the continent.