Earlier quoted context omitted.
There would seem to be precedent for this now. Justice Antonin Scalia died in February of 2016, a replacement was nominated in March of 2016, and because Scalia's seat had become vacant during an election year, the Senate would not even consider a nomination from the president [0]. [0] https://en.wikipedia.org/wiki/Merrick_Garland_Supreme_Court_...
Mitch McConnell and Trump will have a replacement confirmed by the end of October.
The move is to have everything set and ready to go during the lame duck and push hard then if you lose or wait until Jan if you win. Removes the election math from the process.