Pushing back against Republican gains in regions where unions once held great political influence, the Service Employees International Union are an enacting a campaign to elect labor-friendly politicians that will focus largely on the Midwest and Rust Belt. These are states that were once union strongholds, but have lately trended towards electing officials that have fought minimum wage increases and passed right-to-work laws. The SEIU has also gained more clout in those regions in recent years, as the service industry has increasingly replaced manufacturing as a key employment sector.
See "Service Union Plans Big Push to Turn Midwest Political Tide", Noam Scheiber, New York Times, August 25, 2017