Final answer:
The Progressive Party, also known as the Bull Moose Party, emerged in the 1912 presidential election and contributed to the Democratic victory by splitting the Republican vote.
Step-by-step explanation:
In the 1912 presidential election, the creation of the Progressive Party (also known as the Bull Moose Party) contributed to the Democratic Party's victory by splitting Republican votes. The Progressive Party emerged as a third party in response to what its members saw as the domination of U.S. society by big business and a decline in the power of rural communities. Under the leadership of former President Theodore Roosevelt, the Progressives supported policies such as women's suffrage, an eight-hour workday, and workers' compensation, aligning with some of the same reforms called for by the earlier Populist Party. By drawing votes away from the Republican candidate, the Progressive Party effectively aided in the Democratic candidate's win.