Stephen Breyer, both as a judge and Supreme Court Justice, pioneered the foundational logic of the "major questions doctrine," but later opposed its expansion. He originally suggested in 1986 that courts should assume Congress does not delegate major, high-stakes decisions to agencies, focusing them instead on "interstitial" matters. While he provided the conceptual groundwork based on pragmatic statutory interpretation, he later dissented against the current, more restrictive usage of the doctrine.

1986 Origins: Then-Judge Breyer argued that when interpreting statutes, courts should consider whether a legal question is of major economic or political significance.

Pragmatic View: He viewed this as a "useful legal fiction" to manage how Congress delegates power, rather than a strict, formalistic rule.

Administrative Support: Unlike conservative jurists who use the doctrine to curb the administrative state, Breyer as a Justice often found himself in dissent, arguing for more flexibility and agency deference.

Distinction from Current Application: Breyer's original concept was aimed at determining congressional intent in "hard cases," not necessarily as an "outright alternative" to agency deference, as the Supreme Court has later used it.