How were civil liberties violated during WWI?

The story of civil liberties during World War I is, in many ways, even more disturbing. When the United States entered the war in April 1917, there was strong opposition to both the war and the draft. Many citizens argued that the goal of the United States was not to “make the world safe for democracy,” but to protect the investments of the wealthy. President Woodrow Wilson had little patience for such dissent. He warned that disloyalty “must be crushed out” of existence and that disloyalty “was … not a subject on which there was room for … debate.” Disloyal individuals, he explained, “had sacrificed their right to civil liberties.”
Shortly after the United States entered the war, Congress enacted the Espionage Act of 1917. Although the act was not directed at dissent generally, aggressive federal prosecutors and compliant federal judges quickly transformed it into a blanket prohibition of seditious utterance. The administration’s intent in this regard was made evident in November 1917 when Attorney General Thomas Watt Gregory, referring to war dissenters, declared: “May God have mercy on them, for they need expect none from an outraged people and an avenging government.”
Hope this helps!