Since this thread is titled “Historical Ignorance II: Forgotten facts about Lincoln, slavery and the Civil War” I thought your statement implied you agreed with Lincoln's optional War of Northern Aggression. If I misinterpreted your comment, you have my apology.
Once the southern states attempted to secede and launched a war against the Union it most certainly wasn’t optional if Lincoln cared about keeping his oath of office.
He was sacredly sworn to preserve the country of which he was the chief executive officer and commander in chief of the armed forces.