Twombly Doesn't Live Here

Picture a Monday morning in a California superior court law and motion department. The calendar is long, the tentative rulings are due, and the judge picks up a demurrer. Page three, the standard:

"To survive a demurrer, a complaint must contain sufficient factual matter, accepted as true, to state a claim to relief that is plausible on its face."

The judge stops reading the standard section there, because it is the wrong standard. The rest of the brief may be excellent. It now has to overcome a first impression that counsel is not sure which courthouse they are standing in.

Nobody set out to do that. The sentence was drafted, or suggested, by a tool that has read a great deal more federal motion practice than state motion practice. That is not a defect in anyone's character. It is a predictable consequence of what gets written down. Federal pleading law is the most heavily published, indexed, and discussed body of pleading law in the country, and a system that learns from what is written learns plausibility first.

The short version for anyone who needs it: in California state court, a demurrer is decided under Code of Civil Procedure section 430.10(e) and California's fact-pleading rules, not under Twombly and Iqbal, which interpret Federal Rule of Civil Procedure 8(a)(2).

Why the federal cases don't govern

Bell Atlantic Corp. v. Twombly and Ashcroft v. Iqbal are interpretations of a federal rule. Rule 8(a)(2) asks for a short and plain statement of the claim showing that the pleader is entitled to relief, and the Supreme Court read that to require enough facts to state a claim that is plausible on its face. A state court construing its own pleading statute is not bound by the Supreme Court's reading of a rule that does not apply in that court.

California's statute says something different. Code of Civil Procedure section 425.10(a)(1) requires a statement of the facts constituting the cause of action, in ordinary and concise language. That is fact pleading. The general demurrer under section 430.10(e) asks whether the pleading states facts sufficient to constitute a cause of action, and under section 430.30(a) the objection must appear on the face of the pleading or from judicially noticeable matter.

The standard of review comes from California authority, and every California lawyer has read it: the demurrer is treated as admitting all material facts properly pleaded, but not contentions, deductions, or conclusions of fact or law. That line is from Blank v. Kirwan, and the same page supplies the rule on amendment.

Side by side

Notice the fourth row. Both systems refuse to accept conclusions. That overlap is exactly what makes the mistake dangerous. The two standards are close enough that a brief written under the wrong one reads fine until the point where they part company, and they do part company. Twombly itself turned on whether parallel conduct suggested an agreement or was just as consistent with independent action. A California demurrer brief that wants to make that kind of argument needs California authority for it. It will not find that authority in Twombly.

The error also cuts in a direction people do not expect. California fact pleading asks for ultimate facts on every element of every cause of action. A defense brief that argues "plausibility" may actually be understating its own position.

It is not only California

The question in every state is the same: what did the state's court of last resort say about its own rule? The answers differ, and they change.

Two things about that table.

First, it is a starting list, not a fifty-state survey. Do not file on it. Pull the controlling decision in your state and read it.

Second, look at Washington. Twombly retired the old Conley v. Gibson "no set of facts" language for federal courts. Washington kept its traditional standard. So a tool that "modernizes" a Washington brief by swapping in plausibility has made it wrong, and a tool that uses the old Conley formulation in a federal brief has also made it wrong. Same sentence, opposite verdicts, depending on the building. And look at Ohio: a standard can be live at the court of last resort while your brief is in draft. Check the status the week you file, not the year you learned it.

Who pays for this

Follow the error through the building.

The judge pays first, in time. A brief that states the wrong standard has to be translated before it can be decided, and translation is not what a law and motion calendar has room for.

The client pays next. A demurrer argued under the wrong test can lose when it should have won. Worse, it can win in the trial court on reasoning that does not hold up on appeal, which means the client pays twice for one motion.

The small firm pays last, and in the currency that lasts longest. Law and motion judges see the same lawyers again and again. Credibility spent on a standard you should have known does not come back on the next motion.

None of this requires a fabricated case. Every citation in the brief can be real, accurate, and good law. It is the wrong law for the room.

What to do Monday morning

A practical list for any firm filing in state court with AI in the workflow.

1. Name the forum in the first line. Every research request, every prompt, every memo. "California Superior Court, general demurrer under CCP 430.10(e)." A tool that is not told where it is will assume it is in federal court.
2. Keep a banned-phrase list for state filings. "Plausible on its face." "12(b)(6)." "Rule 8(a)." If one of them appears in a California demurrer, someone looks at why.
3. State the standard only from forum authority. The standard section of a state brief cites the state statute and the state's own cases. Federal cases may appear later, for substantive rules of federal law where they apply, never for the pleading standard.
4. Brief leave to amend under the state rule. In California, that means Blank v. Kirwan and the plaintiff's burden to show a reasonable possibility of cure, not Rule 15.
5. Carry the discipline into summary judgment. The same mistake recurs later in the case. A California defendant must present evidence, not simply point out the absence of the plaintiff's evidence (Aguilar v. Atlantic Richfield Co.). The federal Celotex pointing-out route does not travel intact.
6. Ask the tool where each case comes from. For every authority, which court decided it, and which jurisdiction's rule was it applying? If the tool cannot answer that, it cannot be trusted with the standard section.

None of this is sophisticated. It is the kind of thing a good trial judge would tell a new lawyer in five minutes. The difference now is that the tool drafting the first version never heard those five minutes.

Sources: Bell Atlantic Corp. v. Twombly, 550 U.S. 544, 562-63, 570 (2007); Ashcroft v. Iqbal, 556 U.S. 662, 678 (2009); Conley v. Gibson, 355 U.S. 41 (1957); Fed. R. Civ. P. 8(a)(2), 12(b)(6), 12(d), 15(a)(2); Cal. Code Civ. Proc. §§ 425.10(a)(1), 430.10(e), 430.30(a); Blank v. Kirwan, 39 Cal.3d 311, 318 (1985); Aguilar v. Atlantic Richfield Co., 25 Cal.4th 826, 854 (2001); Marshall v. Burger King Corp., 222 Ill. 2d 422, 429-30 (2006); McCurry v. Chevy Chase Bank, FSB, 169 Wn.2d 96 (2010); Cullen v. Auto-Owners Ins. Co., 218 Ariz. 417 (2008); Webb v. Nashville Area Habitat for Humanity, Inc., 346 S.W.3d 422 (Tenn. 2011); Walsh v. U.S. Bank, N.A., 851 N.W.2d 598 (Minn. 2014); Warne v. Hall, 2016 CO 50; Iannacchino v. Ford Motor Co., 451 Mass. 623 (2008); Bethel Oil & Gas, LLC v. Redbird Development, LLC, No. 2024-1696 (Ohio, argued Nov. 19, 2025).