That latter clause is the key, because it drives home that the Senate has two decisions to make in impeachment cases: First, it must decide whether an officer should be removed. Then it must decide whether this person should be disqualified from holding any future federal office. Indeed, of the eight officers the Senate has ever voted to remove, it subsequently voted to disqualify only three of them — reinforcing that removal and disqualification are separate inquiries. And as this procedure and historical practice make clear, by the time the Senate votes on disqualification, the officer has already been removed. In other words, disqualification, at least, is itself necessarily a vote about a former (as opposed to current) officer.
More than that, the disqualification power is both the primary evidence of and the central reason the Constitution allows for the impeachment of former officers. Were it otherwise, an officer facing impeachment, or an officer who has already been impeached and is about to be removed, could also avoid disqualification simply by resigning. In 1876, disgraced Secretary of War William Belknap tried exactly that — resigning minutes before the House vote on his impeachment. The House impeached him anyway, concluding that his resignation did not defeat Congress’s impeachment power. And although some senators ultimately voted to acquit Belknap (who narrowly escaped a guilty verdict) because he was no longer in office, the Senate as a body first concluded that it had the power to try former officers, adopting a resolution that Belknap could be tried “for acts done as Secretary of War, notwithstanding his resignation of said office” before he was impeached.
The Belknap case cemented two precedents: Congress can impeach and remove former officers, but the fact that the defendant is no longer in office is one factor that senators may take into account in deciding whether to vote to convict. So, when President Richard Nixon resigned in August 1974 in an effort to forestall his seemingly inevitable impeachment and removal, that act did not deprive Congress of the constitutional power to still impeach, remove and disqualify him; it merely mitigated the perceived political expediency of doing so. By resigning, Mr. Nixon took at least some responsibility for his conduct. And the circumstances of his resignation left no reason to believe that he would ever again be a candidate for federal office.
But there is no indication that Mr. Trump plans to resign. His term ends next Wednesday only because Section 1 of the 20th Amendment says so. He is not going willingly. And he has made no secret of his interest in running for president again in 2024. What’s more, under the Former Presidents Act of 1958, he stands to receive significant financial and other tangible benefits, including a handsome annual stipend, funds for offices and a staff, and a pension. But that same statute denies such benefits to a former president who was removed “pursuant to Section 4 of Article II of the Constitution.” So whether Mr. Trump is impeached, convicted and disqualified determines not only whether he could ever again hold federal office but may also bear upon the extent to which federal taxpayers will be subsidizing his activities in the years to come.
The conservative argument would say that the Constitution leaves Congress powerless to deal with such a case — or with any scenario in which a president commits grossly impeachable acts in his final days in office. Not so. Whether he should be convicted and disqualified remains, under the Constitution, in the sole purview of the Senate.