What was Abraham Lincoln's belief of secession?

Abraham Lincoln firmly believed that secession was unconstitutional and that the Union was perpetual, meaning states could not unilaterally withdraw from it. He viewed the act of secession as a rebellion against the federal government and a threat to the nation's integrity. Lincoln argued that the Union was formed by the people and could only be dissolved through the consent of the governed, not by individual states acting independently. Thus, he was committed to preserving the Union during the Civil War.