How did western expansion contribute to the secession of southern states, including south carolina

the answer is” Southerners feared that the addition of free states would allow the North to gain more power in Congress.” :)

Explanation:

although world war i began in 1914, the united states did not join the war until 1917. the additional firepower, resources, and soldiers of the u.s. to tip the balance of the war in favor of the allies. remaining neutral. when war broke out in 1914, the united states had a policy of neutrality.