Response or Comment
It frequently happens, in an action by an assignee, that the defendant wishes to use as a cross-action a claim against the assignor. This results in no diffiulty unless the amount of the set-off against the assignor is greater than the claim of the plaintiff, or unless the cross-action calls for a specific remedy against the assigner in addition to its defensive effect upon the plaintiff's demand. In each of these cases we have a three-sided controversy. In the first, the set-off operates against the plaintiff to the extent of his claim and against the assignor for the balance. In the second, the cross-action operates against the plaintiff and his assignor in ways which may be quite variously different. If the assignor can be brought into the controversy, it can be wholly determined in a single action; otherwise two or more actiops are necessary.
Sunderland, Edson R. "Bringing Third Parties into Actions at Law—Set-Off Against the Assignor." Mich. L. Rev. 19 (1921): 540-3.