On September 6, 1901, a self-proclaimed anarchist named Leon Czolgosz fatally shot President William McKinley at the Pan-American Exposition in Buffalo, New York. This paper places the suppression of anarchists and the exclusion and deportation of foreigners in the aftermath of the "shot that shocked the world" within the context of international anti-anarchist efforts, and reveals that President McKinley's assassination successfully pulled the United States into an existing global conversation over how to combat anarchist violence. This paper argues that these anti-anarchist restrictions and the suppression of expression led to the emergence of a "free speech consciousness" among anarchists, and others, and to the formation of the Free Speech League, predecessor of the American Civil Liberties Union (ACLU). Challenging governmental suppression transformed anarchists' identities from violent criminals to free speech defenders. This paper also explores the history, passage, and implementation of the Alien Immigration Act of 1903, which barred and expelled anarchists, those associated with anarchists, and those advocating anarchism, and became the first federal law authorizing the exclusion or deportation of foreigners based on their ideological beliefs, associations, and/or expressions. In United States ex rel. Turner v. Williams (1904), the Supreme Court affirmed the deportation of British philosophical anarchist John Turner and upheld the Alien Act's constitutionality, establishing the precedent for future ideological restrictions of foreigners. This legal precedent paved the way for the mass deportations of radicals after the 1919 Palmer Raids, the exclusion of alleged communist writers, actors, and professors under the McCarran Act of 1950 and the McCarran-Walter Act of 1952, and eventually for a visa denial barring entry to an Islamic scholar under the Patriot Act of 2001.