was a concern that the United States military was not prepared to fight the huge armies of the Central Powers, as the army's last meaningful experience was in the Spanish-American War.  The people of the United States saw the war as a squabble among European powers over territory that did not concern the United States.  The United States only went to war after the discovery of the Zimmerman telegram, which promised Mexico the American West, and the continuation of German unrestricted submarine warfare, which sank many American ships.  Even when the United States joined the war, it did not join as an ally of Britain and France. Instead, the United States was described as an "associated" power.  This was done so the United States could still claim the moral high ground when the conflict ended.  

The United States was very reluctant to enter World War I for several reasons. One reason had to do with trade. We were trading with countries on both sides of the conflict. We knew that if we entered World War I, we would lose our trade with the countries against which we were fighting.

We also knew the war was likely to be a long and costly war. We really had no interest in getting dragged into a war that could last for years and lead to many American casualties. The cost of going to war would also be enormous in economic terms.

There were people who were fearful about what would happen to them if we went to war. It was pretty clearly that we were more supportive of the Allies than of the Central Powers. German-Americans were worried they would face harassment and discrimination if we went to war against Germany.

American interests were different than European interests. We weren’t interested in going to war to gain land. One of our goals was to not get land if we were on the winning side of World War I. When World War I began, we felt the Europeans were making a big mistake by going to war. Little did we know how right that assessment was. The results from World War I and the ensuing Versailles Treaty were some of the factors that led to the start of World War II less than 25 years after World War I ended.

World War I was not the clear-cut case of good versus evil that World War II presented. Many in the US were of British heritage and admired British culture, but many also were German. The Germans aligned with the clean, powerful, and well-run Germany they visited in the years before the war. From the start, it was not entirely easy for the US to take sides.

Further, neutrality made sense to many citizens because of a long tradition, adhered to since George Washington's Farewell Address, of the United States staying out of European affairs. Washington had argued that since the US was young and still weak, it needed to avoid being pulled into European nations's conflicts.

The United States was emerging as the predominant world power in the twentieth century. However, although it was flexing its muscles in the Western Hemisphere, many of its citizens still clung to the idea that what occurred in Europe was not their country's problem. Many resisted the idea of their young men fighting and dying in a war the US did not start and which did not seem to have much to do with US interests.

The war, however, began taking an economic toll. German submarine attacks on American vessels became more costly. In the end, the US intervened on the side of the British because of these attacks and because of the revelation, via the Zimmerman telegram, that the Germans might attack the US via Mexico.

There were many currents of opposition to World War I in the United States. Capitalists such as Henry Ford believed that capitalism was a force for diplomacy and peace, but Ford's mission to forge peace in Europe in 1915 was sadly unsuccessful. Some Irish-Americans were opposed to supporting the British in the war, and some German-Americans opposed joining the war against Germany. Women's groups and religious groups were also in favor of pacifism and believed that the United States should stay out of the war, and the left, including Socialists and Marxists, felt that the war was only for the benefit of the bourgeoisie. These groups supported Wilson during his re-election campaign of 1916, when he ran on the slogan "He kept us out of war." However, when Wilson decided to send American troops to the war in 1917, he argued that fighting in the war would result in greater world peace, as it was "a war to end all wars." Many of the groups that had formerly opposed the war supported Wilson's efforts to fight in World War I to pursue world peace. 

There were people in the United States who were opposed to us joining World War I. Many Americans couldn’t believe the Europeans would be foolish enough to go to war. They didn’t want us to make the same mistake. World War I had the potential to be a very long and a very costly war. Some Americans didn’t want us to be a part of that.

Other people didn’t want to go to war with Germany. This was a sentiment held by many German-Americans. They knew if we went to war against Germany, life for them would become more difficult. They expected there would be discrimination against Germans as well as possible acts of hostility against Germans.

Some people were furious with the British when the war began. Great Britain was interfering with our trade also. Since both sides were interfering with our trade, it was hard to justify choosing one side over the other.

Finally, some of our goals in World War I were very idealistic. Joining this war to make it the last war ever or to make the world safer for democratic governments were goals that would be hard to achieve.

People had valid reasons for us to stay out of World War I.

Many Americans were opposed to the war and wanted to remain neutral. Initially these sentiments were supported by President Woodrow Wilson in his message to the 63rd Congress. The president anticipated negative consequences of the war for the US if they decided to intervene and urged the American people to remain neutral to the war. The need to remain neutral was critical because the American population included citizens of countries engaged in the war. The German-Americans would want success for Germany while French-Americans and British-Americans would wish the same for their countries. The other section of the population opposed the war because it would increase tensions throughout American society, leading to an outbreak of violence on American soil by the American people themselves.

Many people in the United States were very opposed to the idea of getting involved in World War I.  They did not think the war had anything to do with the United States.  They believed that the war was really something that only involved the Europeans -- it wasn't about any big issue that Americans should care about.

Other Americans opposed the war because they did not want the US to take the side of the British.  This was especially true of German immigrants (who liked Germany, of course) and of Irish immigrants (who hated Britain for colonizing their homeland).

Finally, socialists opposed the war because they thought it was just a thing that the rich were doing to get richer.  They didn't want the poor to die for the sake of rich men's profits.