Short answer. You're required to state the necessary party's name (if known) and why they were omitted, per Section 9 of Rule 3. If the court finds your reason unmeritorious, it may order that party included, and ignoring that order without justification waives your claim against them.
What the law says
Whenever in any pleading in which a claim is asserted a necessary party is not joined, the pleader shall set forth his name, if known, and shall state why he is omitted.
Rule 3, Section 9 — Non. Read the full provision →
The pleading requirement itself
Section 9 imposes an affirmative disclosure duty on anyone who leaves out a necessary party: 'the pleader shall set forth his name, if known, and shall state why he is omitted.' This is not optional bookkeeping — it puts the reason for the omission on the record for the court to evaluate, rather than letting a plaintiff simply leave a necessary party out without explanation and hope the gap goes unnoticed. The duty applies even when the necessary party's identity is unknown — in that situation the pleader is not excused from disclosure altogether, only from naming a specific person, since the obligation to state why the omission occurred still applies regardless of whether a name can be supplied.
What happens if the reason doesn't hold up
If the court finds the stated reason for the omission unmeritorious, Section 9 authorizes it to order the omitted necessary party included — but only 'if jurisdiction over his person may be obtained.' The rule does not force joinder at any cost; it is conditioned on the court actually being able to acquire jurisdiction over that person, recognizing that inclusion may sometimes be impossible regardless of the court's preference. Where the necessary party is simply outside the court's reach, the inclusion order cannot issue, and the case proceeds without that party despite the unmeritorious explanation.
The consequence of ignoring the inclusion order
Failing to comply with an order to include the necessary party, 'without justifiable cause,' is deemed a waiver of the claim against that party — a real consequence for non-compliance. But Section 9 also clarifies that non-inclusion of a necessary party does not stop the court from proceeding with the action generally; any judgment rendered is simply 'without prejudice to the rights of such necessary party,' meaning their own rights remain unaffected by a case they were never part of. Taken together, the disclosure duty, the court's conditional power to order inclusion, and the waiver consequence for disregarding that order form a graduated response: disclosure first, then possible court-ordered correction, and only then a real penalty for a party who defies the correction without justification.
Related provisions
- Rule 3, Section 9 — Non
- Rule 3, Section 8 — Necessary party
- Rule 3, Section 7 — Compulsory joinder of indispensable parties