做好法律回击准备，退回美方威胁信函，巴西总统誓言反制美国关税

Core Viewpoint - The article discusses the escalating trade tensions between Brazil and the United States, particularly in light of President Trump's threats to impose a 50% tariff on Brazilian goods, which Brazil's President Lula has vowed to respond to with reciprocal measures [1][2][4]. Group 1: Trade Relations - The U.S. is Brazil's second-largest trading partner, with a trade surplus of $6.53 million for the U.S. in the first quarter of 2025 [6]. - Brazil's recent "Commercial Reciprocity Law" allows the government to impose countermeasures against countries that set unilateral trade barriers, specifically targeting the U.S. [7]. - The U.S. has maintained a trade surplus with Brazil since 2008, with a total surplus of $410 billion over the past 15 years, and a surplus of $6.8 billion in the previous year [4]. Group 2: Political Context - Trump's letter to Lula accused Brazil of "political persecution" regarding the trial of former President Bolsonaro, which has been officially filed by Brazil's Supreme Court [2][3]. - Bolsonaro's son publicly supported Trump's tariff decision, which may backfire politically and aid Lula's re-election efforts [8]. - Lula emphasized Brazil's sovereignty and the independence of its judicial system, rejecting external interference in domestic legal matters [4][5].