What did the election of 1856 show? There was a political divide between the North and the South. A third-party candidate could do well in a presidential election. Slavery was the main issue dividing the main parties.

Slavery was the main issue dividing the main parties.

Explanation:

The election of 1856 in which James Buchanan won as a Democratic presidential candidate, against the Know-Nothings party and the Republican party, shows that "Slavery was the main issue dividing the main parties."

This is evident in the fact that the Democratic party was perceived by the public as a party in support of slavery.

Hence, some Democrats and Whigs party members fall out to form new parties, the Know-Nothing Party, and the Republican party.

The Know-Nothings party has the ideal of anti-immigration, while the Republicans have the anti-slavery ideals.

yes, it can be both.

not concrete, existing in thought or as an idea but not having a physical or concrete existence