Lead: One hundred and fifty years ago the Republic was facing its greatest crisis. This continuing series examines the American Civil War. It is "A House Divided."

Intro: A Moment in Time with Dan Roberts.

Content: In an earlier era little known U.S. presidential candidates who emerged with little obvious support or chances for success were often called “dark horse” candidates. It is an old horse-racing term coined to describe a horse unknown to gamblers who have trouble laying odds on the horse’s potential performance. Abraham Lincoln was one such dark horse. Of those contending for the Republican nomination in 1860, Lincoln was relatively unknown, but had fewer weaknesses.