Administrative Procedure Act

The Administrative Procedure Act, universally shortened to the APA, is the statute that made federal agencies procedurally accountable. Before it, an agency could largely decide how it decided. The APA imposed a sequence that most significant rulemaking still follows: publish a proposal, take comments, respond to them, and publish a final rule that explains the reasoning.

Its second function matters more in practice, because it sets the standard a court applies afterwards. A reviewing court asks whether agency action was arbitrary and capricious, which in plain terms means whether the agency considered the relevant factors and explained itself. That is a test of the record and the reasoning rather than of the policy, and it is why the preamble to a rule is a legal document rather than a courtesy.

Almost every federal court challenge to a regulation is an APA case at bottom, which is why the phrase recurs constantly in coverage of agency litigation. When a rule is vacated, the usual reason is not that the court disliked the policy but that the agency skipped a step the APA required or failed to answer a significant objection filed in the docket.