In the summer of 2025, the government of Brazil suddenly found itself in a deep crisis. The Trump administration had unexpectedly imposed 50 percent tariffs on the country’s products, threatening everyone from coffee planters to shoe manufacturers. At the same time, the United States canceled the visas of eight Brazilian supreme-court justices and placed unprecedented financial and travel sanctions on a powerful justice and his family.Many things about this crisis were novel. For the first time anyone could remember, an American administration had used tariffs not for economic reasons but as a tool to influence the internal politics of a...