This is a no brainer for the unions. Up to 40% voted for Trump already in 2012. The bosses know this. They know that four years ago Obama deliberately abandoned the white working class vote.
Trump does not have to bribe them. All he has to do is assure them that the trade structures that will be put in place will not only assure their jobs, but create incentives for similar jobs to appear. The response by both the Teamsters and the building/Sheet-metal unions has been phenomenal.
The only one he won’t win over is the government service union. That can be crushed by simply reducing government jobs and size.
:)
Issue a cancellation of Kennedy's Executive Order 10988 which allowed government unions.