Anti-Imperialist League
The Anti-Imperialist League was an organization formed in 1898 to oppose the growing trend of imperialism by European powers and the United States. The league included members from various political backgrounds, including socialists, anarchists, labor leaders, humanitarians and former abolitionists. It held its first meeting in Boston on October 15th of that year, with over 10,000 people attending. Its goal was to unite opponents of imperialism across ideological lines and use public education campaigns to raise awareness about the negative effects it had on subjugated peoples around the world. In addition to advocating for non-intervention abroad, they also opposed economic policies such as tariffs that enabled imperial powers to expand their influence overseas at the expense of other countries' sovereignty. They even criticized Ulysses S Grant's administration for annexing Hawaii against its inhabitants' wishes in 1875.
The League became a major force during debates surrounding US interventions into Latin America during Theodore Roosevelt's presidency, which began in 1901; However, membership declined after World War I, when American involvement overseas shifted from territorial expansionism towards economic hegemony through trade deals and investments abroad instead. Despite this decline, it still managed to influence policymakers domestically by pressuring them not to enter into any treaties or agreements that would violate another nation's sovereignty without their consent - something President Woodrow Wilson agreed with but ultimately failed due to his inability to secure support for joining the League of Nations at home following WWI. Though no longer active today, its legacy can be seen in modern anti-war movements, which often argue against interventionism based on similar principles espoused by those involved in the anti-imperialist movement a century ago.