The United States never joined the: Allies
League of Nations
United Nations
Pacific command

the South relied mostly on agriculture therefore needed more slaves

Explanation: The Southern environment is known for its hot and humid subtropical weather where there are long summers and short, mild, winters. This climate favoured agriculture and there were small farms as well as big plantations all over the southern states.

They grew cotton, tobacco, corn, sugar, and rice. The farms relied on slave labour and most of the slaves lived on the big plantations. As a result of this, most Southerners wanted and advocated for slavery as this was tied directly to their livelihood and economy.