I don’t think Hillary is too popular with the Teamsters. They lobbied for years for the Keystone pipeline, and some of those mine jobs could very well be Teamsters as well. In fact I expect the Teamsters and United Mine Workers will endorse Trump.
The teamsters have no problem endorsing a winner, or burying a loser. literally.
those two endorsements would be helpful after Cleveland... or today!
The Teamsters have a history of actually supporting Republicans, however the UMWA will likely do just the same as happened in 2000. In 2000 the National UMWA was all in for Gore, however, at least in WV the locals were showing up at Bush rallies with signs supporting Bush (wearing their hard hats).
They only care about the SEIU, NEA, AFT, and various government employee unions. They know that the UAW is beholden to them.
Democrats don’t care about the industrial trades unions any longer.