A per curiam Supreme Court decision reinforcing that mandamus cannot be used to bypass the final judgment rule.

Allied Chemical Corp. v. Daiflon, Inc. is a shorter, per curiam Supreme Court decision, but it delivers a pointed reminder that continues to shape how lower courts evaluate mandamus petitions challenging interlocutory rulings.

The underlying dispute

The case arose after a court of appeals granted mandamus relief directing a district court to vacate an order granting a new trial, a ruling the Supreme Court found exceeded the proper scope of mandamus review.

The Supreme Court's core message

The Court's opinion emphasized that mandamus is not to be used as a substitute for the regular appellate process merely because a party believes a trial court committed error, however sincerely that belief is held, and however inconvenient the ordinary appeal process may be for the party seeking relief.

Why this decision matters for modern practice

Allied Chemical is frequently cited by courts denying mandamus petitions that, despite creative framing, essentially ask an appellate court to correct a trial court error immediately rather than waiting for the case to reach final judgment through the ordinary process.

The relationship to Kerr and other precedent

This decision reinforces the same line of reasoning found in Kerr and Will, discussed elsewhere in this section — collectively, these cases form a consistent body of Supreme Court precedent cautioning against using mandamus as a general-purpose early appeal.

The lesson for petitioners

Before filing a mandamus petition challenging a trial court ruling, it is worth honestly asking whether the underlying complaint is really about an extraordinary, irreparable harm — or whether it is, in substance, an ordinary disagreement that the regular appellate process is designed to address.