How did the Lincoln's loss turn into a victory

More people realized how terrible slavery was (maybe)

Answer:Explained Below

Explanation:

For preserving the Union and bringing an end to slavery, and for his unique character and powerful oratory, Lincoln is hailed as one of the greatest American presidents.

Despite having a low win chances, Lincoln won with a overwhelming majority of votes. He took every state except few. He received around fifty five % of the popular vote and two hundred twelve electoral votes to McClellan's 21. A huge part of the Union soldiers voted for Lincoln as well, demonstrating their readiness to keep combative and denial to accept defeat.