[x]

He remains the only president elected with only 30 percent of the total vote, since South carolina was excluded from the election.

According to the accepted totals, Lincoln got almost 40% of the vote.

From what I can see "South Carolina" the state did "vote" in the election. Their electors cast ballots.

It was just that the state decided up to the Civil War, not to hold popular elections. Since the state chose not to play the popular vote game, you can't hold it against the victors in those elections.

[JCBreckenridge]

Given that Lincoln claimed South Carolina was part of the union - you can’t exclude them from the total. Lincoln won no votes south of the Mason Dixon. When you do that, Lincoln’s share drops to 36 percent of the entire US.