The United States has spent the past five years pushing to reduce its reliance on China for computer chips, solar panels and various consumer imports amid growing concern over Beijing’s security threats, human rights record and dominance of critical industries. But even as policymakers and corporate executives look for ways to cut ties with China, a growing body of evidence suggests that the world’s largest economies remain deeply intertwined as Chinese products make their way to America through other countries. New and forthcoming economic papers call into question whether the United States has actually lessened its reliance on China —...