Rule 12.Defenses and objections; when and how presented; by pleading or motion; motion for judgment on pleading.

Rule 12(a) gives a defendant 30 days after service of the summons and complaint to answer, and gives the same 30 days for an answer to a crossclaim or a reply to a counterclaim labeled as such. Filing a motion under this rule resets that clock: once the court rules on the motion or postpones its disposition until trial, a responsive pleading is due within 20 days, extended to 20 days after service of a more definite statement if the court orders one. A separate provision addresses cases removed to federal court: once removal is filed, the state court takes no further action unless and until the case is remanded, at which point the defendant and other parties get 30 days from the remand order to plead.

Rule 12(b) lets a party raise, by motion instead of in a responsive pleading, any of seven defenses: lack of subject-matter jurisdiction, lack of personal jurisdiction, improper venue or division, insufficiency of process, insufficiency of service of process, failure to state a claim upon which relief can be granted, and failure to join a necessary party. Joining several of these defenses in one motion or pleading does not waive any of them, and obtaining an extension of time to answer does not waive any defense either. If a Rule 12(b)(6) motion to dismiss for failure to state a claim relies on matters outside the pleadings that the court does not exclude, the motion converts into one for summary judgment under Rule 56, with both sides given a reasonable chance to present material relevant to that standard. Rule 12(c) applies the same conversion rule to a motion for judgment on the pleadings, available after the pleadings close but before the trial is delayed.

Rule 12(e) lets a party move for a more definite statement when a pleading is too vague or ambiguous to answer, pointing out the defects and the details wanted; if the court grants the motion and its order goes unheeded, the court may strike the pleading or make another appropriate order. Rule 12(f) lets the court strike, on motion or on its own initiative, any insufficient defense or any redundant, immaterial, or scandalous matter from a pleading.

Rule 12(g) and (h) govern waiver: a party who moves under this rule but omits an available defense or objection generally cannot raise it in a later motion, and lack of personal jurisdiction, improper venue, insufficient process, and insufficient service of process are all waived if omitted from an early motion or from the responsive pleading (or a permitted amendment). By contrast, failure to state a claim, failure to join a necessary party, and failure to state a legal defense may be raised in any permitted pleading, by motion for judgment on the pleadings, or at trial — and a court must dismiss on its own if it appears the case lacks subject-matter jurisdiction at any point in the proceeding.