Declaratory Judgments and Compulsory Counterclaim

Do compulsory counterclaims exist in simple declaratory judgment suits?  Generally no, writes Judge Posner in Allan Block Corp. v. County Materials Corp.   It's really a nice opinion that delves deeper than does my summary below.

When a declaratory judgment plaintiff asserts no coercive claims, and the declaratory judgment defendant asserts no counterclaims, claim preclusion is not triggered.  In other words, a judgment granting or denying declaratory relief is not claim preclusive.  Easy enough for the plaintiff, who is free therefore to assert related claims in a later suit because a plain ol' declaratory request doesn't trigger the rules of merger and bar.  (The plaintiff would of course be constrained by issue preclusion).  Reaching the question of compulsory counterclaims requires an additional step.  The civil rules define certain counterclaims as compulsory, but it's actually claim preclusion that bars the counterclaims the rules define as compulsory.  That is when the plaintiff seeks coercive relief, claim preclusion--not the compulsory counterclaim rule alone--operates to bar defendants from asserting  counterclaims when they are defined as compulsory.  But since a pure declaratory judgment does not trigger claim preclusion, and since claim preclusion is what bars the later assertion of a compulsory counterclaim, there's generally no such thing as a compulsory counterclaim in a pure declaratory judgment suit.  Or perhaps more precisely, there's no bar against later asserting a counterclaim even when it's defined as compulsory.   --RR