United States Department of Commerce v. Montana

Background

The State of Montana and its officials sued the federal Government after the 1990 census reduced Montana from two Representatives to one, arguing Congress’ automatic formula did not give the Nation the greatest possible equality of people per Representative and therefore violated the Constitution.

Reasoning

The Court considered whether the strict intrastate “one-person, one-vote” standard should apply to how seats are divided among the States. It concluded that because the Constitution requires at least one Representative per State and fixes the total House size, perfect equality among all States is impossible. Given that history, congressional discretion, and a long record supporting the 1941 “method of equal proportions,” the Court gave deference to Congress’ choice and reversed the District Court’s ruling that struck down the statute.

Real world impact

The decision leaves the automatic equal‑proportions formula in place and affirms that Congress may adopt and apply a consistent mathematical method after each census. Montana’s challenge failed, so its single-district status stands. The Court’s reasoning makes it harder for states to overturn apportionments simply by showing an alternative formula would produce a different seat allocation.

Dissents or concurrances

A judge in the lower court had dissented, arguing a “practical approximation” test should govern and that alternative formulas, such as the harmonic‑mean method, would have given Montana a second seat. The Supreme Court majority declined to adopt that approach.