What is the ally doctrine?

Answer 1

Ally doctrine in Labor Law is the doctrine that allows a union to picket a secondary employer who is doing the work of the primary target's union workers for the primary employer. E.g. when Company A employees go on strike, Company A hires out to Company B the work previously being done at Company A. The union may picket at Company B because they are an "ally" of Company B. Usually Company B must know that they are doing the contract work for Company A. See, Royal Typewriter Co.