What qualifies a claim as "compulsory" for joinder?

A claim is considered "compulsory" for joinder when it arises from the same transaction or occurrence as the main claim. This idea is rooted in the notion that it is efficient and just for all related claims to be resolved together in a single lawsuit to avoid inconsistent verdicts and to ensure that all parties involved can fully litigate their interests. The compulsory nature is established by the Federal Rules of Civil Procedure, which encourage the joinder of claims that share a significant factual connection.

The other options focus on unrelated elements that do not determine the "compulsory" nature of a claim. The jurisdiction in which a claim is filed, or whether it is universally applicable in any court, does not inherently affect whether it should be joined with other claims. Additionally, a plaintiff's voluntary decision to join claims does not establish them as compulsory, as compulsory claims are mandated by their relationship to the main claim's facts rather than the plaintiff's choice.