[1] Adam Clayton Powell Jr., a senior member of the United States House of Representatives, was embroiled in scandal, specifically around allegations that he had refused to pay a judgment ordered by a New York court, misappropriated congressional travel funds, and paid his wife a congressional staff salary for work she had not done.

When the 90th Congress convened in January 1967, Speaker of the House John William McCormack asked Representative Powell to abstain from taking the oath of office.

[4] In an opinion by Warren E. Burger, soon to be Chief Justice of the United States, the court held that the federal courts did have subject-matter jurisdiction, but dismissed the case on two grounds: that Powell lacked standing to sue, and that the case represented a non-justiciable political question.

[5] While the suit was making its way through the court system, Powell was re-elected in the 1968 election and was ultimately re-seated in the 91st Congress.

The majority opinion was authored by Chief Justice Warren, and signed by Black, Brennan, Douglas, Harlan, Marshall, and White.

The opinion stated that the case was justiciable, and it did not constitute a political question that pitted one branch of government against another.

I, § 6) do not preclude judicial review of Constitutional issues raised in the case (but not necessarily in all cases touching upon the subject of speech and debate or Congress's judging the qualifications of its members) because "no branch is supreme," and it is the duty of the court to ensure that all branches conform to the Constitution.

The Court found that Congress is the whole body of initially candidate members who have been elected by the laws of the several states (in and for each state's apportioned congressional districts), who assemble at the seat of the federal government on the 3rd day of January after the preceding November's congressional elections.

The Court did not reach, because it determined it did not need to in this case, the question of which Congress the Constitution was referring to that had the power to expel one of its members.

The Court found that if the Congress went beyond a determination that a candidate member had satisfied the Constitution's qualifications for membership and had been duly chosen by and through the laws of their state, it could not, under the Constitution, go further in examining and possibly reject a candidate member before administering the oath of office and seating him.

The Court looked at the historical precedent of the House, the history of its candidate members, and the role of the states and their voters in choosing their representatives.

The people, by their Constitution, affirmatively posited, defined, and delimited all qualifications for standing in elections for membership in the Congress.