What’s the deal with Roberts not presiding?

[pdq]

Scotusblog:

The Constitution specifies only four points about the Senate impeachment trial of a president: (1) The Senate “shall have the sole power to try all impeachments”; (2) when sitting as a court of impeachment, senators “shall be on oath or affirmation”; (3) conviction of any accused officer requires “concurrence of two thirds of the members present”; and (4) when the president is the accused, “the Chief Justice shall preside.”

Sounds pretty clear to me. BTW, Trump is impeached, and this happened (twice, actually) during his term. The fact the Senate didn’t want to deal with the trial before he left office doesn’t invalidate the constitutional requirements for the trial, IMHO.