At Volokh, Ilya Somin blogs about the impeachment of (former Judge) Thomas Porteous. At the end of the post, Somin quips:

In addition, the Senate also voted 94–2 to bar Porteous from holding federal office in the future. So no one need worry about him getting elected to Congress, as impeached judge Alcee Hastings did.

I’m not sure if this is correct.

Article I, Section III of the Constitution Provides:

Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of Honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.

The Senate voted on the following question, which mirrored the language of Article I, Section III:

On the Motion (Motion to Forever Disqualify G. Thomas Porteous, Jr. to Hold and Enjoy Any Office of Honor, Trust, or Profit Under the United States )

I do not think the office of Senator or Representative would be considered an “Office . . .  under the United States.” This would seem to refer only to executive branch officials. Further, the eligibility requirements for Congress are set in the Constitution. Under U.S. Term Limits v. Thornton, states cannot add additional requirements onto service in the Congress.  I’m not sure if Congress can. Perhaps as Judge of their own elections, they could disqualify Thomas Porteous, were he to ever be elected to Congress, but I find this tenuous.

Commenter CrazyTrain at Volokh makes a similar point.

I hope you realize Ilya that to the extent the Senate meant to ban Porteous from being elected to Congress or the Senate, such an attempt would clearly be unconstitutional (not that there is any chance that he will be elected so such office). The Constitution defines the qualifications of being elected to Congress, etc., and the Senate cannot vote to change those qualifications.

Although, assume an executive branch official is impeached, and he is barred from holding any officer under the United States. Assuming a person meets all other qualifications for the Presidency, would he be barred?

Assume Bill Clinton was impeached during his first term, and ran for the Presidency again in 2000. What if the electoral college somehow elected Clinton? The House could not be judge of that election (unless there was a tie in the electroal college). Would this issue even be justiciable?