The Framers envisioned a system were multiple (= more than 2) popular candidates gaining significant numbers of votes, with the EC electing the President (and the House choosing the President if the EC was deadlocked). Thus, the anti-slave Lincoln being elected President because D Party votes were divided between two candidates was not exceptional. It was what the Framer of the Constitution expected. What Lincoln would have done had the southern states not seceded is probably not guessable.