The idea is to make it look as if Smith is not sufficiently pro-labor to earn their support. Perhaps, only days before the election, either Jones drops out of the race to stops campaigning and labor gets the word out that they're really for Smith. Save knock out punch for last item before election day. Critical Mass - 1. Overwhelm opposition with endorsements, money or physical presence and activity at a critical point.
Sheer volume counts.
When you cannot beat your opponent with persuasion or mobilization based on the issues and message differences, try crushing them with muscle, money or activity. Good against lazy front runners. Get opposition into a position that they cannot escape. Surround your opponent and deprive them of a safe way out. Build solid pockets of political support that cannot be penetrated by the opposition under any circumstances.