In the 1850s, the issue of slavery caused a split in politics. The two major political parties at that time were the Democratic Party and the Whig party. Both of them had Southern and Northern groups. The two national parties were breaking off into smaller groups. They were divided along geographical lines. Northern groups opposed slavery. Southern groups supported it.
New parties were springing up. There was the People's party, the American "Know-Nothing" party, and the Free-Soil party, along with others. In 1854, the Republican Party was created. The name was chosen to honor Thomas Jefferson. That was the name used by his party. The Republican Party opposed the Kansas-Nebraska Act. This Act would have allowed slavery in these new territories. The Republican Party soon became the main political power in the North.