Even when the Dems ran separate candidates in 1860 (Douglas for the North and Breckenridge for the South, I think), Lincoln won both the popular vote and the electoral college.
I'd be up for a replay of that in '08
Lincoln won more of the popular vote than either Douglas or Breckenridge--however, he did not win a majority of the popular vote, he simply won a majority in the "winner take all" electoral college. The whole point of that passage in history is that the Republicans did not win so much as a fatal split in the Democrats lead them to lose. If you count all of the people in 1860 who voted for Douglas and
Breckenridge, which is to say, traditional Democratic voters, it is pretty obvious that Lincoln would have been buried in a land slide if the Democrats had not split.