Seems like Mitch thinks he’s setting a trap for Dems… the Democratic field (namely Biden).
If Biden came out and said “Due to the solemn nature of the impeachment proceedings, I am suspending my ground campaign out of respect for Senators Warren, Sanders, Booker and Klobuhcar” he would pretty much ensure Pete does the same.
It would call Mitch’s bluff.
Further, would be smart if one of the campaigns (Sanders would be best) made this suggestion. It would put pressure on Biden to take one for the team and to show loyalty to a core Democratic cause.