Which affirmative defense is never waived?

• A. Non-joinder of a nec party
• B. Failure to state a CoA
• C. Lack of SMJx
• D. All of the above

Answer: (D)

The defenses being tested are all about fundamental limits on a case: whether the court has power to hear it, whether the right parties are in place to grant complete relief, and whether the plaintiff has pleaded a legally recognizable claim. Lack of subject matter jurisdiction means the court simply lacks authority to decide the case, so this issue can be raised at any time, even by the court on its own initiative, and it cannot be waived by the parties’ agreement or silence. If a necessary party is not joined, the court cannot provide complete relief or adjudicate the dispute properly; that defect must be addressed and can prevent the case from going forward until proper joinder is resolved. And if the complaint fails to state a valid claim, the case cannot stand on the merits; while amendments may cure pleading defects, the deficiency itself is not a matter that the parties can sign away or waive without consequence. Taken together, each of these issues is non-waivable, so the correct choice includes all of the above.