The Teamsters called on Cummins to "act socially responsible" and treat its workers well. The Teamsters says Cummins violates labor laws and teats workers unfairly. The Cummins' website is quite on the conflict, but you can read the Teamsters' account of the protest here.
The main story on the Teamsters' website right now is a reaction to the recent decision to allow certain trucks from Mexico further into the United States than before. You can read our coverage here and see the Teamsters' ideas here.