Prior to the United States' entry into World War I, competing support for the Allies and the Central Powers divided the country. America, the land of immigrants, had citizens with ties to both sides, and some Americans vigorously protested the war. The federal government took action to stop such protests. President Wilson issued a proclamation establishing regulations for the conduct and control of enemy aliens. Congress passed the Espionage Act of 1917, which made it illegal to interfere with the war effort or obstruct military recruitment, and the Sedition Act of 1918, which made it illegal to make false statements about the government or to interfere with the war effort. In October 1918, Congress also passed the Alien Act, which provided for the deportation of "any alien who, at any time after entering the United States, is found to have been at the time of entry, or to have become thereafter, a member of any anarchist organization."

"The great demand for wartime production during World War I made it possible for thousands of Pennsylvania workers to demand higher wages and overtime pay. But these gains came at a price, as the federal government's War Labor Board, created in 1918, also cracked down on strikes and coerced many workers into signing yellow dog contracts that halted new union organization.

After the war, a surge of more than four million striking American workers demanded that wages stay at wartime levels, and that employers create pension and benefits plans. The great steel strike of 1919 against U.S. Steel brought out 350,000 workers who shut down the industry in ten states. In Pennsylvania, armed company guards flanked the Allegheny Coal and Coke Company buildings and murdered labor organizer Fannie Sellins and miner Joseph Strzelecki. Mayors in mill towns across western Pennsylvania banned public gatherings and arrested, fined, and jailed many, like Mother Jones, who dared to speak without a permit in Homestead. In Pittsburgh, the sheriff deputized 5,000 U.S. Steel employees to keep the peace, while the Pennsylvania State Police clubbed strikers at meetings in Clairton and Glassport. U.S. Attorney General A. Mitchell Palmer, a former pro-labor congressman from Stroudsburg, Pennsylvania, launched a series of raids to break into union offices, confiscate papers, and arrest 6,000 alleged radicals in thirty-three cities, including Philadelphia and Pittsburgh. By January 1920, the strike ended in tragic defeat and fear of radicalism exploded in a 'red scare.'"
(ExplorePAHistory, Labor's Struggle to Organize, Chapter Three: Between the Wars: 1919-1938)

Against this backdrop of federal legislation and worker unrest, many Americans made a connection between labor unions at home and communist ideas in Europe. The increasing flow of immigrants now included people from Southern and Eastern Europe, many of whom came from countries that followed either socialist or communist political ideology. Many of these individuals joined forces with frustrated American workers in an attempt to boost union membership and power and secure improved working conditions and wages. The fear of a radical labor revolution, supported by the recent Russian Revolution, created a climate of suspicion and fear in America. The press and the federal government nurtured the first "red scare" through political cartoons and legislation. Legitimate labor demands became radical plots and America no longer was a welcoming nation to the world's oppressed people.

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