The correct answer is C) it created divisions that ended the Whig Party and split the Democratic Party.
The effect that the issue of slavery had on politics in the 1850s was that it created divisions that ended the Whig Party and split the Democratic Party.
Some Whigs from the North supported the abolition of slavery but many Whigs in the South supported slavery because the economy of the South depended so much on the use of slaves to grow cash crops that needed to be exported to Europe. Years later, with the election of Abraham Lincoln in November 1860, divisions increased between the northerners and the southerners.