President Donald Trump says car companies are thriving due to tariffs and other key policies he's instituted as president. During a rally this week at a General Motors facility in Michigan, the Republican drove the point home repeatedly, saying his tariffs had revived domestic auto production. However, tariffs have cost Michigan businesses billions of dollars and fueled inflation. Michigan, in particular, faces economic challenges given its deep ties to Canada, which Trump has singled out for a new round of import levies. Some auto companies plan to increase U.S. production, but the benefits from those efforts won't be immediate. While Trump's base remains loyal, economic worries are beginning to surface.