What was the main reason the Republican Party desired to control both houses of Congress and the Presidency?

A.) They would be able to write laws to support and expand slavery.
B.) They would be able to write laws supporting prohibition.
C.) They wanted to have the Dred Scott decision overturned.
D.) They would be able to end slavery in the Western Hemisphere.
E.) They would be able to write laws to prevent slavery in the new territories.