It is simple most of the really contested races in this election are being run on traditional Democrat TURF. Can you say Mo, MN, SD, New Jersey? Define Democrat turf. Define where the contests are.
When the FIGHT IS OVER DEMOCRAT TURF, then really big Democrat Democrats are an asset.
This is an off year election and most races in contest are being fought on Democrat turf.
When you are playing Atomic Bombs with Japan over Hiroshima... even a draw is a huge victory.