What must a party demonstrate when filing a motion to dismiss based on joinder issues?

When a party files a motion to dismiss based on joinder issues, demonstrating a procedural defect in the joinder is essential. This is because joinder rules are designed to ensure that all necessary parties and claims are included in a single action to promote judicial efficiency and prevent inconsistent verdicts. A procedural defect could involve various issues, such as failure to comply with the rules governing joinder, such as not having a necessary party join the suit, or improperly joining parties that do not share similar claims.

By effectively showcasing a procedural defect, the moving party can argue that the case should not proceed in its current form because it does not adhere to the required legal standards for joinder. This reinforces the importance of proper party alignment in a lawsuit, ensuring that all issues are resolved in one action whenever possible.

The other options, while they might be relevant in different contexts, do not address the specific criteria for challenging joinder itself. Evidence of unclean hands pertains to equitable defenses, improper jurisdiction is more about the competency of the court for the lawsuit, and flaws in the original complaint could relate to substantive legal issues rather than the procedural aspects of how parties are joined. Thus, focusing on the procedural defects directly aligns with the goals of proper joinder practice.