Roberts is solely responsible for the FISA court. As suchh heh is a fact witness in thhe illegal activities that occured leading to the FISA court approval of spying on thhe Trump campaign and administration.
It would be a first order of business for the defense team to demand Robert’s recusal as chair of the impeachment trial. His failure to recuse himself would create a genuine constitutional crisis with no appeal other than his impeachment. That is, the Senate could refuse to allow him to sit in the trial.
Robert’s recusal would require that he resign from the Court, allowing Trump to appoint Thomas as Chief Justice. That would put an activist conservative judge in the top position on the Judicial branch of government. In point of fact this needs to happen.
For the Trump doctrine to move forward Roberts needs to come off the court and Thomas appointed as Chief Justice.
Roberts can only be removed through impeachment in the House and conviction in the Senate, voluntary resignation. The Constitution provides no provision for the Senate to refuse to allow the Chief Justice to chair the Senate trial of the president. Furthermore, looking at the current composition of the Senate there isnt a majority vote to remove Roberts from office much less 2/3, even if the Constitution permitted the Senate to stop Roberts from chairing the upcoming Trump trial.
If Roberts were to die or resign prior to the trial of President Trump, the President can nominate whoever he wishes to be Chief Justice but the Senate must approve the nomination before the new Chief Justice can be seated. It is doubtful the Senate will take on the appointment of a new Chief Justice, particularly one nominated by the President being tried, before the impeachment trial.
Finally, if something happened to Roberts, if you want to change the direction of the court for decades do you really want to appoint a man in his 70s to the position of Chief Justice or do you nominate a strong conservative jurist who is much younger. Nominate a minority or white female aged 40-55 for the role who has impeccable credentials. Democrat Senators will be put in the position of opposing the appointment of the first minority or female to Chief Justice. Plus the Democrats running for President will have to go on record opposing or supporting the nomination. Their base will be pushing to oppose but if the nominee has stellar character, independent voters will not support opposing a historic appointment.
and then replace Thomas with another great conservative.
The sooner, the better.