Final answer:
Had Theodore Roosevelt not run as a third-party candidate in 1912, William Howard Taft likely would have had a better chance at winning the election, but it's not possible to state this with absolute certainty.
Step-by-step explanation:
If Theodore Roosevelt had not run as a third-party candidate in 1912, it is widely believed that William Howard Taft, the Republican incumbent, would have been more likely to win the election over Woodrow Wilson, the Democratic candidate. During the 1912 election, the split in the Republican vote between Taft's conservative supporters and Roosevelt's Progressive Party, or Bull Moose Party, adherents effectively handed the presidency to Woodrow Wilson. It is important to note, however, that it's impossible to determine with certainty the outcome had Roosevelt not run, but historical evidence suggests that Taft would have consolidated the Republican vote in the absence of Roosevelt's third-party challenge.