The federal Rule 12(b)(6) motion: one shot, 14 days after denial, and the trap in Rule 12(g)

The motion to dismiss for failure to state a claim is the most-filed motion in federal civil practice, and the rule around it is built to be used once. Rule 12(g)(2) bars a second Rule 12 motion raising anything that was available and left out, and Rule 12(h)(1) turns four of the seven defenses into forfeitures if you get the sequence wrong.

When it must be filed

Rule 12(b): every defense must be asserted in the responsive pleading if one is required, "But a party may assert the following defenses by motion":

(1) lack of subject-matter jurisdiction; (2) lack of personal jurisdiction; (3) improper venue; (4) insufficient process; (5) insufficient service of process; (6) failure to state a claim upon which relief can be granted; and (7) failure to join a party under Rule 19.

A motion asserting any of these defenses must be made before pleading if a responsive pleading is allowed.

Before pleading. File an answer first and the motion route closes — though Rule 12(h)(2) preserves the substance of some defences by other means.

And joining defences costs nothing: "No defense or objection is waived by joining it with one or more other defenses or objections in a responsive pleading or in a motion."

The underlying deadline

Rule 12(a)(1)(A): a defendant must serve an answer

(i) within 21 days after being served with the summons and complaint; or (ii) if it has timely waived service under Rule 4(d), within 60 days after the request for a waiver was sent, or within 90 days after it was sent to the defendant outside any judicial district of the United States.

Waiving service is worth 39 extra days, which is the point of Rule 4(d).

Counterclaims and crossclaims — Rule 12(a)(1)(B): 21 days after being served with the pleading that states them. A reply to an answer — (C): 21 days after being served with an order to reply.

The United States — Rule 12(a)(2): the United States, a federal agency, or a federal officer or employee sued only in an official capacity must answer within 60 days after service on the United States attorney.

Federal officers sued individually — Rule 12(a)(3): 60 days after service on the officer or on the United States attorney, whichever is later.

What filing the motion does to the clock

Rule 12(a)(4): unless the court sets a different time, serving a Rule 12 motion alters the periods:

(A) if the court denies the motion or postpones its disposition until trial, the responsive pleading must be served within 14 days after notice of the court's action; or (B) if the court grants a motion for a more definite statement, the responsive pleading must be served within 14 days after the more definite statement is served.

Fourteen days from notice of the court's action — not from entry of a written order, and not from the date you read the docket. On a motion denied in a long opinion, that is a short runway for an answer you may not have drafted.

Evidence converts the motion

Rule 12(d):

If, on a motion under Rule 12(b)(6) or 12(c), matters outside the pleadings are presented to and not excluded by the court, the motion must be treated as one for summary judgment under Rule 56. All parties must be given a reasonable opportunity to present all the material that is pertinent to the motion.

Three consequences.

Conversion is automatic, not discretionary, once the court declines to exclude the material.

It applies to 12(b)(6) and 12(c) only — not to the jurisdictional defences, where courts may consider evidence without converting anything.

And everyone gets a chance to respond. Conversion cannot be sprung at the hearing; the parties must be given the opportunity Rule 56 contemplates.

The practical lesson: attaching a declaration to a 12(b)(6) motion is a decision to file a summary judgment motion, on Rule 56's terms and timetable. The guide on federal summary judgment timing covers those.

Rule 12(g): the one-motion rule

Rule 12(g)(1) — you may join: "A motion under this rule may be joined with any other motion allowed by this rule."

Rule 12(g)(2) — and you must:

Except as provided in Rule 12(h)(2) or (3), a party that makes a motion under this rule must not make another motion under this rule raising a defense or objection that was available to the party but omitted from its earlier motion.

So the first Rule 12 motion is the only one. Anything available and left out cannot come back by motion, except through the two escape valves in Rule 12(h)(2) and (3).

This is why a Rule 12 motion should be drafted last, after every defence has been catalogued — not first, because the 12(b)(6) argument was the obvious one.

What is waived, and what survives

Rule 12(h)(1) — the four that die. A party waives any defence listed in Rule 12(b)(2)–(5) — personal jurisdiction, improper venue, insufficient process, insufficient service — by:

(A) omitting it from a motion in the circumstances described in Rule 12(g)(2); or (B) failing to either (i) make it by motion under this rule; or (ii) include it in a responsive pleading or in an amendment allowed by Rule 15(a)(1) as a matter of course.

Note the saving route: an amendment as a matter of course under Rule 15(a)(1). That window is 21 days after serving the pleading, or 21 days after service of a responsive pleading or a Rule 12(b), (e) or (f) motion, whichever is earlier. An amendment by leave will not do it. The guide on amending federal pleadings covers the timing.

Rule 12(h)(2) — the three that survive. Failure to state a claim, failure to join a person required by Rule 19(b), and failure to state a legal defence may be raised:

(A) in any pleading allowed or ordered under Rule 7(a); (B) by a motion under Rule 12(c); or (C) at trial.

So a 12(b)(6) argument is never truly lost — but it loses the chance to end the case before discovery, which is the only reason to make it early.

Rule 12(h)(3) — subject-matter jurisdiction is never waived: "If the court determines at any time that it lacks subject-matter jurisdiction, the court must dismiss the action." On its own, at any stage, including after judgment.

The other Rule 12 motions

Judgment on the pleadings — Rule 12(c): "After the pleadings are closed — but early enough not to delay trial — a party may move for judgment on the pleadings." Same conversion rule under Rule 12(d).

More definite statement — Rule 12(e): available for a pleading "so vague or ambiguous that the party cannot reasonably prepare a response." The motion "must be made before filing a responsive pleading and must point out the defects complained of and the details desired." If a granted order is not obeyed within 14 days, the court "may strike the pleading or issue any other appropriate order."

Motion to strike — Rule 12(f): the court may strike "an insufficient defense or any redundant, immaterial, impertinent, or scandalous matter," acting on its own or on a party's motion made before responding — or, where no response is allowed, within 21 days after being served with the pleading.

Pre-trial hearing — Rule 12(i): if a party so moves, any Rule 12(b)(1)–(7) defence, whether raised in a pleading or by motion, and a Rule 12(c) motion "must be heard and decided before trial unless the court orders a deferral until trial."

The sequence that keeps everything

How the federal rule compares

Oregon is the outlier worth knowing about: ORCP 21 F lets a defendant file a standalone personal jurisdiction or service motion without consolidating anything, and ORCP 21 A(2)(b) lets the court decide most defences on evidence without converting to summary judgment. The guide on the Oregon motion to dismiss covers both.

A short checklist

1. Calendar 21 days from service — or 60, or 90, if service was waived under Rule 4(d).
2. Catalogue every Rule 12(b) defence before you draft. The first motion is the only one.
3. Join them all. Rule 12(b) says joining waives nothing; Rule 12(g)(2) says omitting forfeits.
4. File before answering. A responsive pleading closes the motion route.
5. Decide deliberately about attaching evidence. Rule 12(d) converts the motion, and the conversion is mandatory once the court does not exclude the material.
6. Diary 14 days from notice of a denial — the shortest deadline in the sequence.
7. If you find a missed jurisdiction, venue, process or service defence, use the Rule 15(a)(1) as-of-course amendment, and move quickly; leave to amend will not preserve it.
8. Subject-matter jurisdiction is always available — to you, to the other side, and to the court on its own.

Where these rules live

• FRCP 4 — Summons
• FRCP 7 — Pleadings allowed; form of motions
• FRCP 8 — General rules of pleading
• FRCP 9 — Pleading special matters
• FRCP 12 — Defenses and objections
• FRCP 15 — Amended and supplemental pleadings
• FRCP 19 — Required joinder of parties
• FRCP 56 — Summary judgment

This page explains what the rules say. It isn't legal advice, and the plausibility standard courts apply on a Rule 12(b)(6) motion comes from case law this site doesn't cover.