During the 1860 presidential election, Abraham Lincoln promised to: c. prevent states from leaving the Union. Therefore c. prevent states from leaving the Union is correct .
Abraham Lincoln, as the Republican candidate in the election of 1860, campaigned on a platform that primarily focused on preserving the Union.
The Southern states were concerned about the potential abolition of slavery, a topic that heightened sectional tensions.
Lincoln, while personally opposed to the spread of slavery into new territories, reassured the Southern states that he had no intention of interfering with slavery where it already existed.
Lincoln's commitment to preventing states from seceding was a response to the growing secessionist sentiment in Southern states, which escalated following his election.
His dedication to maintaining the Union was a central tenet of his presidency and became a crucial factor leading to the outbreak of the American Civil War in 1861.
Ultimately, Lincoln's presidency was defined by his efforts to preserve the Union, address the secession crisis, and later, with the Emancipation Proclamation, shift the focus of the war toward the abolition of slavery as a means of strengthening the Union's moral cause.