I like the "idea" of unions (i.e. collective bargaining to protect workers), but they are so corrupt and poorly run that they are more trouble than they are worth. They protect the shitty workers from being fired and prevent the company from making it's own promotion/hiring decisions. The dues are usually skimmed by the union bosses' and the rest of the pot is used as a PAC for the left. When it comes time for negotiations (holding the company hostage), they feed the workers propaganda to whip them up in a frenzy against the company that is responsible for their livelihood.
I'd say we do away with them completely, but there are decent unions out there that aren't on a mission to fuck everybody else to get theres.
Then there are the public unions that are negotiating against the taxpayers. Un-fucking-real. Of course it makes sense to elect corrupt politicians that will be their bitch. It's a never ending gravy train.