During the economic crisis in 2007, the United Auto Workers was forced to accept two-tiered contracts to keep factories open. These contracts created a second pay scale for new employees that paid them less than other workers. The potential for this to become permanent is quite scary. In the UAW’s failure to win a majority vote in the Chattanooga Volkswagen plant, the two-tiered contract was cited by union opponents as a reason not to join the UAW. Even if that was just cover for already existing anti-unionism, it was still quite damaging.
Luckily, the UAW, including rank and file workers, are working hard to fight back against the two-tiered systems as those contracts signed 5 and 6 years ago come up for renegotiation. Of course, employers have a number of tools at their disposal to pay workers less, including the use of subcontractors and the threat of capital mobility. So this is a hard fight but at least the resistance is real and there is hope that the system will end.