The issue of slavery was largely responsible for the party realignment that followed the election of thomas jefferson in 1800 abraham lincoln in 1860 william mckinley in 1896 franklin roosevelt in 1932

The issue of slavery was largely responsible for the party realignment that followed the election of Abraham Lincoln in 1860.

Explanation:

In the presidential election of 1860 Abraham Lincoln was elected 16th President of the United States of America.

There were four major presidential candidates, Abraham Lincoln, who stood for the Republicans, John Cabell Breckinridge for the Southern Democrats, Stephen Arnold Douglas for the Northern Democrats, and John Bell for the United States Constitutional Union, which had formed from the Whigs.  

Since the Republicans were in favor of the abolition of slavery, southern states declared their independence in the months following the election and joined forces with the Confederate States, leading to the Civil War.

c) legal battles last five weeks after the election due to the narrow victory in several states.