In the context of the debates over slavery, what did Lincoln argue regarding its expansion into territories?

Abraham Lincoln argued that slavery should not expand into new territories, as he believed that it was morally wrong and detrimental to the principles of freedom and democracy upon which the United States was founded. Lincoln held that the federal government had a responsibility to prevent the expansion of slavery into the western territories, which was a significant component of his platform during his political career and, notably, his presidency. His position was rooted in the belief that allowing slavery to spread would undermine the efforts to contain it, ultimately leading to its further entrenchment in American society.

Lincoln's perspective directly contested the notion of popular sovereignty, where the residents of a territory would decide whether to permit slavery. He feared that this approach would lead to the proliferation of slave states. Additionally, he rejected the argument that slavery was a constitutional right that should be protected, contending that the Founding Fathers envisioned a nation moving towards freedom rather than accepting the continuation of an institution they recognized as morally flawed. This context is vital for understanding the broader debates over slavery and sectional tensions leading up to the Civil War.