Vice President Kamala Harris and her running mate, Gov. Tim Walz (R-MN), used Labor Day to court U.S. workers in the Midwest as they seek to preserve Democrats’ long-standing alliance with unions.

Harris, the Democratic presidential nominee, touted her support for labor organizations to a crowd of supporters in Detroit while flanked by top union representatives, including United Auto Workers President Shawn Fain and American Federation of Teachers President Randi Weingarten.