President Joe Biden on Tuesday joined a picket line with striking autoworkers in Michigan, supporting their call for a 40% pay raise and saying they deserve a “lot more” than they are getting.

Biden’s appearance, the first visit by a U.S. president to striking workers in modern history, comes a day before Donald Trump, the Republican front-runner for president, will speak to auto workers in Michigan. The rare back-to-back events highlight the importance of union support in the 2024 presidential election, even though unions represent a tiny fraction of U.S. workers.

Democrat Biden traveled to a Belleville, Michigan, parts distribution center owned by General Motors (GM.N), and joined dozens of picketers outside. “Companies were in trouble, now they’re doing incredibly well. And guess what? You should be doing incredibly well, too,” Biden said through a bullhorn. “Stick with it.”