Did the American public support World War I? Did it support the Spanish-American War more?

American public support was stronger for the Spanish-American War than for World War I because during the Spanish-American War, the U.S. was in support of imperialism, while by World War I, there was a strong current of progressivism and pacifism in the country. In addition, while the Spanish-American War was fought against Spain (and fought in Cuba, Puerto Rico, and the Philippines), World War I was fought against Germany (and many Americans were of German...

American public support was stronger for the Spanish-American War than for World War I because during the Spanish-American War, the U.S. was in support of imperialism, while by World War I, there was a strong current of progressivism and pacifism in the country. In addition, while the Spanish-American War was fought against Spain (and fought in Cuba, Puerto Rico, and the Philippines), World War I was fought against Germany (and many Americans were of German descent).

The Spanish-American War was fought largely for reasons of imperialism. The United States saw European nations colonizing territories around the world, and America wanted to be an empire as well. In addition, the United States wanted raw materials, such as sugar, from Cuba and Puerto Rico, and the U.S. wanted the Philippines as a naval station. For these reasons, the U.S. became involved in fighting against Spain, which controlled these territories. Once the U.S. gained them, we took them over rather than granting them full independence, leading to resistance, particularly in the Philippines. Many Americans supported the war because they wanted the U.S. to become a major imperial power, though some thought that taking over these countries would lead to an influx of immigrants who would challenge native-born Americans for jobs. In addition, the press, including the "yellow press" put out by William Randolph Hearst and Joseph Pulitzer, whipped up public opinion in favor of the war. These newspaper magnates published stories about the horrific treatment of the Cubans by the Spanish, and their sensationalist reporting also led to public support of the war.

World War I had far less American support. The European part of the conflict started in 1914, and Woodrow Wilson ran for re-election as President in 1916 on a policy of neutrality in the war. His slogan was "he kept us out of war." He had conducted his first term in office as a progressive president and passed a great deal of reforms, including anti-trust legislation. A tide of progressivism swept over the country. Influenced by progressivism, many Americans did not support joining the war, which they thought was motivated by greed. Wilson convinced them to join only when he argued that U.S. involvement in the war was necessary to keep the world safe for democracy.  In addition, many Americans were of German descent, so they did not support a war in which our country would be fighting against Germany. Many Americans were also of Irish descent, and they did not support fighting with England. 

Opposition to World War I was strong. In 1917, the U.S. government passed the Espionage Act (which declared interfering with the war or helping enemies of the country illegal), followed by the Sedition Act in 1918. This act increased the number of behaviors that could be targeted by the Espionage Act and included a prohibition against saying or printing anything against the government or the war. Several hundred people were convicted using this law in 1919 and 1920.