* Regional support: Buchanan was a native of Pennsylvania, which was a swing state in the 1856 election. He was also able to win support from other Southern states, as he was seen as a moderate on the issue of slavery.
* Democratic Party loyalty: Buchanan was a long-time member of the Democratic Party, and many voters were loyal to the party regardless of their views on the issues.
* Lack of a strong alternative: Buchanan's main opponent in the election was John C. Frémont, a member of the new Republican Party. Frémont was seen as too radical on the issue of slavery for many voters, and he did not have the same level of support as Buchanan within the Democratic Party.
* Economic conditions: The economy was doing well in 1856, and many voters were reluctant to change leadership at a time of prosperity.
In addition to these factors, it is also worth noting that voter turnout was relatively low in the 1856 election. This may have benefited Buchanan, as it is possible that some of his supporters were more motivated to vote than were his opponents.