US leaders were nervous that the imposition of a military draft could meet with strong opposition. However, because they approached the draft in a way that did not play favorites, the country accepted the draft process.
During the Civil War, when Congress enacted a draft to supply soldiers to fight for the Union army, riots broke out in New York City. A provision of the Civil War draft allowed wealthier men to avoid being drafted by paying a fee that would hire a substitute to go to war for them. This was seen as anti-democratic and unfair to lower class working men.
The draft instituted during World War I was carried out with a greater sense of equity and fairness. Writing for the Smithsonian, Annika Lundeberg explains: "President Wilson's Selective Service Act of 1917 differed from the Civil War's conscription act of 1863 in that those who were drafted could neither purchase an exemption nor hire a substitute to take their places. Exemptions and substitutions during the Civil War were unpopular with many, as only the wealthy could afford to evade military service. With the option of substitution off the table, the Selective Service Act was more acceptable to many during the Great War."
US leaders thought that people would oppose to a general military draft during World War I. This was also the reason why they didn't opt for this choice immediately but rather waited to see how the war would progress.
Expansionist justified the idea of Manifest Destiny because they said they were spreading democracy. They wanted everybody to be live like they do and to be democratic and what better way to do that than by spreading the word to the people living on the land that they already conquered.
