What a Supreme Court case 50 years ago tells us about Roy Moore

Wikipedia - 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.

Powell was re-elected in the 1966 election. In January 1967, the 90th Congress convened, Speaker of the House John William McCormack asked Representative Powell to abstain from taking the oath of office. The House adopted H.Res. 1, which stripped Powell of his House Committee chairmanship, excluded him from taking his seat, and created a select committee to investigate Powell's misdeeds. After the select committee conducted its investigation and hearings, in March 1967, the House adopted H.Res. 278 by a vote of 307 to 116, which excluded Powell from Congress and also censured him, fined him $25,000, took away his seniority, and declared his seat vacant.

Powell, along with 13 of his constituents, filed suit in the United States District Court for the District of Columbia, naming McCormack and five other representatives as defendants...

[A Supreme Court] opinion stated that the case was justiciable, and it did not constitute a political question that pitted one branch of government against another. Rather, it required "no more than an interpretation of the Constitution."

The opinion stated also that Congress being the sole judge of its members' qualifications  and the Speech and Debate Clause 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 majority opinion held that Congress does not have the power to develop qualifications other than those specified in Art. I, § 2, cl. 1-2.

Article I, section 5, of the U.S. Constitution states that "Each house shall be the judge of the... qualifications of its own members," but then immediately states that each House has the authority to expel a member "with the Concurrence of two thirds." The Court found that it had a "textually demonstrable commitment" to interpret the clause, which, in this case, the Court did. The Court's interpretation was that the subject clause meant that the process that led to the expulsion of a member, duly sworn and enrolled upon the body's rolls, was the only method for a House to give effect to its power to determine the qualifications of its members.

The Court reasoned that the authority of Congress in this matter was post facto: That is, it attached only after a member-elect had been elected under the laws of the state in which the congressional district was located, and after said member-elect took the oath of office.