Final answer:
Woodrow Wilson won the presidency in 1912 due to the split in the Republican Party, with Roosevelt forming the Progressive Party and dividing the conservative vote. His Progressive ideals, appeal as a political outsider, and a campaign later focused on military preparedness and keeping the U.S. neutral helped him win the election and a second term in 1916.
Step-by-step explanation:
Woodrow Wilson won the presidency in 1912 primarily because of a split in the Republican Party. Former President Theodore Roosevelt broke away from the Republicans to form the Progressive Party, which resulted in a significant division of the conservative vote between him and the incumbent Republican President William Howard Taft. This division allowed Wilson, the Democratic candidate, to win the presidency with just 42 percent of the popular vote. Wilson, a Progressive governor of New Jersey and former president at Princeton University, had academic credentials and a reputation as an outsider from Washington politics that appealed to many Progressive reformers.
During his first term, Wilson supported various Progressive ideals and policies, and despite his initial victory being due to the split in the Republican Party, he implemented a "preparedness campaign", which strengthened the U.S. military. His efforts to keep the U.S. out of World War I—at least initially—proved to be a strong campaign position in 1916 when he won reelection by a slim margin.
The electoral success of the Democratic Party in 1912 was also bolstered by their control of Congress, having won a House majority in 1910 and gaining control of the Senate in 1912. The Democrats benefited from Roosevelt's defection from the Republicans, which largely damaged their chances of retaining the presidency and control of Congress.