The threat of imposition of tariffs on oil imports from key trading partners like Canada, Mexico, and China is reshaping the dynamics of crude flows and refining economics in North America. While such a development has been put on hold, these tariffs, which range from 10% to 25%, particularly target heavy and sour crude, a critical feedstock for U.S. refiners can significantly impact U.S. energy security and have reverberations across the global oil markets.