If I understand your question, you want to know if P. Trump can remove John. Roberts as Chief Justice and appoint one of the other S.C. Justices, that is, not remove him from the SC just reassign him within the supreme court?
The Presidents power with respect to the SC extends only to nominating an SC Justice, in Roberts case, he was nominated to fill the specific position of Chief Justice of the SC. All the other power...of confirmation and removal (impeachment) lies with the Senate.
The POTUS has the sole power to name a Chief Justice of the SCOTUS. Have you seen anything that says that that appointment is for life?
But more to the point, why not do like the Dems and challenge the practice if the need arises and serves our purpose? For example, the Dems want to make D.C. a state... that should clearly be unconstitutional! ...but they keep talking about doing it anyway!
The difference is that the Dems pull this stuff and get away with it - because the 'pubbies don't fight; the 'pubbies don't try such things because the 'pubbies don't fight!
The Dems have redistricted 'pubbies out of practically any representation in about a dozen states - e.g. Massachusetts! The 'pubbies just shrug and move on. The 'pubbies try fair redistricting in one state, Texas, and the Dems are ready for a civil war!
Interesting question.
The position is actually “Chief Justice of the United States.”
The position of Chief Justice is only mentioned in Article 1 Section 3 Clause 6 (Impeachment) in the Constitution.
The Constitution is silent on advice & consent of the Chief Justice appointment though that has been the process for accepting the Chief Justice.
Had Pres. Bush kept Roberts as the nominee for O’Connor and appointed someone who was already an Associate Justice as CJ, could the CJ then be replaced as CJ by an existing Associate and the former CJ goes back to being and an Associate without being impeached ?
That answers my question about Roberts.