Since the question was asked earlier in this thread; the following is the oath all of the Senators just took:
So at least McConnell and Graham have already declared their intent to break that oath.
"I solemnly swear (or affirm, as the case may be) that in all things appertaining to the trial of the impeachment of (the person on trial), now pending, I will do impartial justice according to the Constitution and laws; So help me God."
So at least McConnell and Graham have already declared their intent to break that oath.