In 1816 William Crawford was offered the Democratic-Republican nomination. He refused in favor of James Monroe, believing the 20s to be his time in the sun. Of course Monroe went on to serve two terms, and when Crawfords chance in 1824 came, a paralyzing stroke left him a deadweight in the political circus that developed out of the election.
What if he had accepted the 1816 nomination? Obviously he would have defeated Rufus King in 1816, but how would a Crawford presidency have differed from Monroe's?