Need fast
the antebellum period was a time of sectional struggle between the north and the south. describe how three of the following key terms made sectionalism worse in the years before the civil war.

the missouri compromise
the compromise of 1850
the fugitive save law
dred scott v. sanford
the wilmot proviso
invention of the cotton gin
mexican-american war
kansas-nebraska act

The Antebellum period is considered the period before the civil war. The next three events made sectionalism worse before the war.

1.- The Missouri Compromise.

To maintain the balance of power in Congress where polarization between slave and free states was becoming an unsolvable problem, the Missouri Compromise was approved in 1820. The Act allowed Missouri as a slave state and Maine as a free state.  

In 1823, the Missouri Compromise was declared unconstitutional by the Supreme Court in the Dred Scott decisión. The decisión stated that Congress did not have the authority to prohibit slavery in the states.

2.- The Mexican-American War .

With the Mexican war against the United States(1946-1948), derived from the U.S. annexation of Texas in 1945, the Abolitionists saw the war as an attempt by the states that approved slavery to extend it even more and increase their power with the creation of additional slave states out of recent “acquired Mexican” territories-.

3.- The Kansas-Nebraska Act.

Probably, the Kansas-Nebraska Act was the main reason to start the civil war. People who wanted to move to Nebraska was not allowed to do so until the land was organized as a territory. People couldn't legally hold a claim on that land.  That portion of the land had been prohibited slavery by the Missouri Compromise.

the answer is selfishly. hope this !

"a government in which power is divided between state and national levels". federalism is a system of government in which entities such and state and province, share power with the national government.