Final answer:
Most of the country turning against slavery and the split in the Democratic Party helped Lincoln win the presidency in 1860.
Step-by-step explanation:
The factor that helped Lincoln win the presidency in 1860 was the fact that most of the country had turned against slavery. This issue was a major dividing point, and Lincoln's opposition to slavery resonated with a significant portion of the population. Additionally, the Democratic Party was split into multiple factions, weakening their support and ultimately leading some Democratic opponents to endorse Lincoln. While Lincoln did have national political experience, it was ultimately his stance on slavery and the fractured state of the Democratic Party that contributed to his victory.
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