Understanding John Roberts role and limits? I found this Atlantic article helpful to understand exactly how Roberts' job is defined in this matter. It's not as I previously thought. "As the country searches for something solid and dispassionate in the midst of political spectacle, it will benefit, on balance, from seeing the chief justice presiding. Not because he will serve as a judge, but because he won’t. Not because he will force any major rulings, or save the Senate from itself, but because he can’t. The question of removal lies in the hands of 100 people constitutionally assigned to answer it. It’s out of Roberts’s hands."
https://www.theatlantic.com/ideas/archive/2019/12/john-roberts-senate-trial/603724/
