The factor that helps explain why Abraham Lincoln won the election of 1860 is:
- Democrats were divided.
In the 1860 election, the Democratic Party was split into two factions: Northern Democrats, who supported Stephen A. Douglas, and Southern Democrats, who backed John C. Breckinridge. This division allowed Lincoln, the Republican candidate, to win a plurality of the electoral votes despite not being on the ballot in many Southern states. The other options listed do not accurately capture the main reasons for Lincoln's victory in that election.