- The Republican Party's dominance in American politics: The Republican Party had won every presidential election since 1868, and Roosevelt's popularity allowed him to easily secure the Republican nomination.
- His charisma and progressive policies: Roosevelt was a charismatic leader with a reputation for taking action, and he was popular among voters for his progressive policies, which included trust-busting, consumer protection, and strengthening labor unions.
- His handling of the Spanish-American War: Roosevelt gained national fame during the Spanish-American War, serving as the commander of the Rough Riders, a volunteer cavalry regiment. His leadership and bravery in the war helped him to become a national hero.
- The weakness of the Democratic Party: The Democratic Party was divided and lacked a strong leader, which made it difficult for them to mount an effective challenge to Roosevelt.
As a result of these factors, Roosevelt won the 1904 presidential election in a landslide, defeating Democratic candidate Alton B. Parker by over two million votes.