Short answer. Section 8 of Rule 3 defines that second category: a necessary party is 'not indispensable' but ought to be joined if complete relief is to be accorded to those already parties, or for a complete settlement of the claim. Unlike indispensable parties, the case can still proceed and be finally resolved without them.
What the law says
A necessary party is one who is not indispensable but who ought to be joined as a party if complete relief is to be accorded as to those already parties, or for a complete determination or settlement of the claim subject of the action.
Rule 3, Section 8 — Necessary party. Read the full provision →
A necessary party is not required for a valid judgment
Section 8 draws a clear line by contrast: a necessary party 'is not indispensable.' That single clause is the key distinction from Section 7's indispensable parties, whose absence prevents any final determination of the action at all. A necessary party's absence does not carry that consequence — the court can still validly decide the case and enter a binding judgment among the parties who are actually before it, even without the necessary party.
Why join them anyway
Even though not strictly required, Section 8 explains why a necessary party's presence still matters: joining them helps ensure that 'complete relief' is accorded to the parties already in the case, and helps reach a 'complete determination or settlement' of the claim. Their absence does not doom the case, but it may leave loose ends — relief that is only partial, or a settlement of the dispute that does not fully account for everyone with a stake in it. This is what binds counsel to at least attempt joinder of a known necessary party rather than ignoring the question, even knowing the case can technically go forward without them.
Practical effect on how a case proceeds
Because a necessary party's absence is not fatal, courts and litigants have more flexibility here than with indispensable parties: the necessary party can often be brought in later, or the case can simply proceed to judgment without them if joinder proves impracticable, with the understanding that the relief granted may be less than fully complete. This flexibility is the practical payoff of the 'not indispensable' language that opens Section 8's definition. That flexibility does not mean joinder is discouraged — Section 8 still frames it as something that 'ought to' happen — only that failing to achieve it does not derail the litigation the way an indispensable party's absence would. A court weighing whether to press ahead without a necessary party is essentially deciding whether the incompleteness that results is an acceptable cost of resolving the dispute among the parties actually before it.
Related provisions
- Rule 3, Section 8 — Necessary party
- Rule 3, Section 7 — Compulsory joinder of indispensable parties
- Rule 3, Section 9 — Non