28 U.S.C. § 1447(c) provides that, “A motion to remand the case on the basis of any defect other than lack of subject matter jurisdiction must be made within 30 days after the filing of the notice of removal.”
In other words, after a party (presumably the defendant) removes a case from state court to federal court, there is a 30-day time limit to make a motion to remand (return) the case back to state court.
However, this 30-day limit only applies where there is some sort of defect in the removal to federal court. The 30-day limit does not apply if the federal court lacks subject matter jurisdiction. A case must be remanded to state court if the federal court lacks subject matter jurisdiction, regardless of whether more than 30 days have passed.
Example: 30-day limit applies
For example, let’s say a defendant removes a case to federal court from state court, however, defendant failed to attach a required document to the removal papers. Failure to attach the required document is a procedural defect and 1447 (c) imposes a 30-day limit for another party to move to remand the case back to state court.
Example: 30-day limit does not apply
Defendant removes a case to federal court on grounds of diversity subject matter jurisdiction. Among other things, diversity subject matter jurisdiction requires that no plaintiff be a citizen of the same state as any defendant. After more than 30 days it becomes evident that plaintiff and defendant are citizens of the same state.
In this example, a party could move to remand the case back to state court, or the federal court could return the case to state court on its own. When a federal court lacks subject matter jurisdiction the case must be remanded to state court at any point before final judgment. The 30-day limit in 28 U.S.C. 1447(c) does not apply.