A plea of a matter of which a dissolution is sought by the action is null.

Explanation

(English-origin maxim.) When a suit seeks to dissolve or annul a matter, the defendant cannot plead that very matter in bar — the thing sought to be destroyed cannot serve as its own shield.

Where this applies

• A tenant sues to void a lease obtained by fraud, and the landlord cannot use that same lease as a defense — the thing being dissolved cannot shield itself.
• A shareholder sues to annul a corporate merger, and the merged company cannot plead the merger as a bar to the lawsuit.
• A party sues to rescind a contract, and the other side cannot use the contract's arbitration clause as a defense because the very validity of the contract is what is being challenged.