Agency procedures are drawn from four sources of authority: the APA, organic statutes, agency rules, and informal agency practice.

However, Congress may further limit the scope of judicial review of agency actions by including such language in the organic statute.

The authority of administrative agencies stems from their organic statute, and must be consistent with constitutional constraints and legislative intent.

The regulation is outside the agency's statutory purpose as articulated in its organic statute.

Agencies may not promulgate retroactive rules unless expressly granted such power by the organic statute.

The opinion stands for how courts review administrative agencies' interpretations of their organic statutes.

If the organic statute unambiguously expresses the will of Congress, the court enforces the legislature's intent.

Unlike some other members of the court, Stevens has been consistently willing to find organic statutes unambiguous and thus overturn agency interpretations of those statutes.

The scope of authority held by an agency is determined by the agency's organic statute.

The FCC's authority stemmed from its organic statute, the Communications Act of 1934.