As the United States marks the 250th anniversary of its founding, it confronts a new world order dominated by its relationship with China. In this wide-ranging series, we examine the pressure points and possibilities in those ties, from hard tech to soft power. Here, Teresa Elena Frontado and Igor Patrick look at how Beijing is testing long-standing US influence in the western hemisphere. Asked during the 2024 presidential campaign whether he was concerned about Brazil and Mexico drifting...