Hmmm...it occurs to me that SCOTUS acted without cause.
In January of 1967, following allegations that Powell had misappropriated Committee funds for his personal use and other corruption allegations, the House Democratic Caucus stripped Powell of his committee chairmanship. The full House refused to seat him until completion of an investigation by the Judiciary Committee. In March the House voted 307 to 116 to exclude him. Powell won the special election in April to fill the vacancy caused by his exclusion, but did not take his seat.
In June of 1969 the Supreme Court ruled that the House had acted unconstitutionally when it excluded Powell, and he returned to the House, but without his seniority. Again his absenteeism was increasingly noted.
I would presume that Tennesse has a right to judge the returns of its own elections which is what it seems they were doing in this case. The Federal Courts have no right to intervene in this though because the elections of state legislators is outside their jurisdiction.
SCOTUS did not act improperly in the Powell case. The House didn't *expel* Powell, since one can't expel a member until he has been seated. The House decided to *exclude* Powell under Article I, Section 5, but did so for reasons that were not included among the qualifications for a Representative in the Constitution. The House could have seated Powell and then expelled him, but the Democrat leadership that ran the House knew that they wouldn't be able to get 2/3 of members to vote to expel Powell (I guess it's easier to get votes to exclude than to expel, especially when the person knows that he'd get excluded with anythong above 50%+1, so the person knows that he won't be blamed by black voters for Powell's exclusion), soo they illegally excluded him. After the Court ruled for Powell and he was sworn in to the House, the House could have expelled him then, but it didn't have the 2/3 needed; the House did strip Powell of his seniority, which after all is an internal House rule that cannot be challenged by the courts.