Can a plaintiff bring together a federal claim and a related state claim in one lawsuit according to Rule 18(a)?

The ability to bring together a federal claim and a related state claim in one lawsuit is indeed governed by Rule 18(a), which allows a party to join multiple claims in a single action. When both claims arise from the same set of facts, they are considered related, thereby meeting the criteria for permissive joinder under this rule. This can enhance judicial efficiency by resolving multiple claims that are connected and can prevent inconsistent judgments that might arise from separate lawsuits addressing the same underlying events.

The principle behind this rule aims to streamline litigation and reduce the burden on both the court and the parties involved, as it consolidates related matters into one case. Therefore, if a plaintiff has a federal claim and a related state claim that arise from the same facts, they can properly join those claims in one lawsuit.

The other options do not accurately reflect the conditions under which claims may be joined. The monetary amount of the state claim does not determine whether it can be joined with a federal claim, nor does the residence of the defendants or the diversity status of the federal claim affect the ability to join related claims under Rule 18(a).