How did president Lincoln attempt to preserve the union over the slavery issue?

President Lincoln sought to preserve the Union primarily by taking a moderate stance on slavery, aiming to balance the interests of both free and slave states. He initially focused on preventing the expansion of slavery into new territories rather than abolishing it outright. The Emancipation Proclamation in 1863 marked a strategic shift, framing the Civil War as a fight for freedom while also weakening the Confederacy's labor force. Ultimately, Lincoln believed that preserving the Union was essential for achieving a long-term solution to the slavery issue.