On September 4, 2026, the Supreme Court of Justice of the Nation (SCJN) published jurisprudence P./J. 179/2026 (12a.) (digital record 2032601), which answers a practical question for those of us who negotiate, structure, and litigate commercial contracts: if a party sues in court for the nullity of an arbitration agreement—the pact by which parties decide to resolve their disputes before arbitrators rather than in court—can the judgment be appealed? The Court ruled that it can.
Before this jurisprudence, two Collegiate Courts had held opposing views on the matter, which in legal terms is known as a contradiction of criteria. The Fourth Collegiate Court in Civil Matters of the First Circuit considered that no appeal was possible, while the Second Collegiate Court in Civil Matters of the Fourth Circuit held that an appeal was indeed permissible.
The Fourth Collegiate Court analyzed the issue in light of the special arbitration regime and, in particular, Article 1432 of the Commercial Code, which declares that a resolution in which a judge reviews a decision by an arbitral tribunal that has declared itself competent is not subject to appeal. Under that logic, allowing an appeal would disregard the purpose of that regime: for issues regarding arbitral competence to be resolved definitively and without unnecessarily prolonging the proceedings.
The Second Collegiate Court, on the other hand, distinguished that scenario from the case in which one of the parties goes directly to a judge to sue for the nullity of the arbitration agreement before an arbitral tribunal has ruled on its own competence. For this court, that constitutes an ordinary commercial lawsuit subject to general rules of challenge, meaning the judgment can indeed be appealed. The difference, then, lay in determining which scenario Article 1432 regulates and which regime applies to a nullity action filed independently.
To understand the difference, it is helpful to start with the text of the articles involved. Article 1424 of the Commercial Code states:
“The judge to whom a dispute is submitted regarding a matter that is the subject of an arbitration agreement shall refer the parties to arbitration at the request of either party, unless it is proven that said agreement is null, ineffective, or impossible to perform.”
For its part, Article 1432 states:
“The arbitral tribunal shall be empowered to rule on its own competence, including any objections with respect to the existence or validity of the arbitration agreement. For that purpose, an arbitration clause which forms part of a contract shall be treated as an agreement independent of the other terms of the contract. A decision by the arbitral tribunal that the contract is null and void shall not entail ipso jure the invalidity of the arbitration clause.”
In this article, "compromissory clause" is another term for an arbitration clause. And, for our purposes here, the same article adds that if the arbitral tribunal declares itself competent before resolving the merits of the case, any party may request a judge, within 30 days of being notified of that decision, to resolve the matter definitively: "a resolution that shall be unappealable".
The difference between the two articles is fundamental. Article 1424 starts from a dispute that is already in the hands of a judge: there is an arbitration agreement, and one of the parties requests that the matter be sent to arbitration. The judge must do so, unless it is proven that the agreement is null, ineffective, or impossible to perform.
Article 1432, on the other hand, starts from an arbitration proceeding that is already underway. In that case, it is the arbitral tribunal itself that first decides whether it is competent, even in the face of doubts regarding the existence or validity of the arbitration agreement. This is the principle known as kompetenz-kompetenz —the arbitrator decides on their own competence—, which is included in the UNCITRAL Model Law on international commercial arbitration. If the arbitral tribunal declares itself competent, the parties may subsequently go to a judge, but the judge's decision is unappealable. Furthermore, the autonomy of the arbitration clause means that the validity of the main contract and that of the arbitration agreement are analyzed separately: the fact that a contract is void does not, by that fact alone, imply that the arbitration clause is also void.
The SCJN, in resolving the contradiction, distinguished between both scenarios and concluded that an appeal is indeed admissible against a judgment issued in an ordinary commercial trial in which the nullity of an arbitration agreement is claimed, and that such an appeal must be exhausted before resorting to an amparo, the constitutional defense trial. In other words, the unappealability provided for in Article 1432 does not extend to any judicial ruling related to the validity of an arbitration agreement, but rather to the specific scenario that the article regulates: one in which the arbitral tribunal has already ruled on its competence and, subsequently, a judge resolves the matter.
The jurisprudence is mandatory as of September 7, 2026.
Beyond the procedural issue, we believe this jurisprudence offers an important reflection for those of us involved in the negotiation and drafting of contracts: an arbitration clause should not be a routine clause. If the parties truly want to reduce litigation, the way they construct their arbitration agreement deserves special attention. A deficient, ambiguous, or questionable clause can result in the parties having to go through litigation to determine if arbitration can even take place before they can ever discuss the merits of the dispute before an arbitrator.
The paradox is interesting: we choose arbitration to avoid the courts, but a dispute over the arbitration clause itself can lead us before a judge first. Are we designing our arbitration agreements with that perspective in mind?
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