How did the United States prepare for World War I?

The act of entering any kind of war is not an action taken lightly. The U.S. government faced many obstacles at the prospect of entering into WW1. Leonard Woods and Theodore Roosevelt led a campaign to strengthen the U.S. military when the war first began.

In 1915, a movement began and argued that the U.S. needed to build strong naval and land forces thinking the U.S. would eventually be in the war. There was strong opposition to this. It moved quickly through Protestant churches and women's groups. The Democratic party also saw this as a threat. Theodore Roosevelt was a strong candidate for the presidency. The problem was, the U.S. military was, in fact, not ready or in shape to enter war.

In 1917 the Germans sunk one of the U.S. naval ships, and this was the event that pushed us into war. The U.S. had to make the American people understand that war was the right answer. They had to convince businesses that they would succeed and not fail during the war. The war itself, still faced opposition, but for the most part Americans supported our military in their efforts. The entry into the war, was one that was not taken lightly. The U.S. went to great lengths to make sure our military was as prepared as they could be, and the rest of Americans knew the risks and benefits of going to war with Germany, of course this wouldn't be the last war we had with Germany. This war prepared the U.S. for the horrors they were soon to face.

The US had to do a few things to prepare for entry into WWI.  Among them were:

• Persuasion.  The government needed to persuade the people that going to war was the right thing to do.  This was done through the Committee on Public Information.
• Coordination with business.  The US government could not or did not want to simply tell businesses what to make to help the war effort.  Instead, the government tried to coordinate its needs with those of business.  It offerred good prices for the things it wanted made and it tried to persuade businesses to act out of patriotism to make what was needed.
• Training the military.  The US had to draft soldiers to fight in the war and it had to train them to do so effectively.

In these ways, the US prepared for entry into WWI politically, economically, and militarily.

How did the United States mobilize for World War I?

Part of the mobilization effort was to mobilize popular opinion for the war after four years of strict neutrality. This was achieved through two methods. First, the US government moved to silence speech through anti-sedition legislation and regulating the mail. Second, propaganda that emphasized the perfidy and brutality of the Germans appeared in the form of posters, pamphlets and government-solicited newspaper editorials. The Committee for Public Information, headed by George Creel, sent operatives around the country to give speeches in support of the war effort.

Another facet of mobilization was the shift of heavy industry to a wartime footing. Unlike in Europe, the government did not nationalize industry, but they did set quotas for production in crucial industries under the War Industries Board, led by Bernard Baruch. To avoid the necessity of rationing food, the Food Administration, under Herbert Hoover, subsidized important crops and emphasized cooperation among food distributors to avoid price gouging. 

Finally, and perhaps most important, the US government instituted Selective Service shortly after declaring war. Thousands of young men were conscripted into the service and sent to training camps, where they received a quick, often insufficient training regimen before being sent to Europe. In the spring of 1918 alone, close to one million American young men were sent to France.