It is absurd to act like that letter gave him any authority to do anything or that it had any legal meaning at all.
from what i understand, it is debatable whether he had the power to reject unlawful Electoral College certificates or not- Pence claimed he did not- others claim he did and that it had been done before in history- The letter wasn’t to ‘give him authority’ to do it- He may have the authority already to reject the electors-
Pence is a coward!