The admission of Missouri as a slave state was controversial in the Senate because

:the Senate was pro-slavery
:it would create sectionalism
:it would upset the balance***
:The Senate was anti-slavery

Am I right?

You're right.

WHICH ONE IS YOUR ANSWER?????

IT WOULD UPSET THE BALANCE???

You are partially correct. The admission of Missouri as a slave state was indeed controversial in the Senate, but the correct reason is that it would upset the balance. Allow me to explain the historical context and reasoning behind this.

During the early 19th century, there was a delicate balance between free states (where slavery was prohibited) and slave states within the United States. The U.S. Senate was particularly concerned about maintaining this equilibrium, as it ensured equal representation of both interests.

With the admission of Missouri as a slave state in 1821, the existing balance of power would be disrupted. At that time, there were already an equal number of states representing both sides of the slavery debate. However, if Missouri were admitted as a slave state without any provisions to maintain the balance, it would have tipped the scales in favor of the pro-slavery faction.

This imbalance raised concerns among those who opposed slavery, as it could potentially lead to an expansion of slavery into new territories. Consequently, the Senate engaged in intense debates and negotiations over how to address this issue and maintain the political equilibrium.

In the end, a compromise was reached known as the Missouri Compromise of 1820. It admitted Missouri as a slave state but also added Maine as a free state to preserve the balance. Additionally, it established a boundary line (the 36°30′ parallel) beyond which slavery would be prohibited in future territories, except within the state of Missouri.

So, to summarize, the controversy surrounding Missouri's admission as a slave state in the Senate was primarily due to the concern that it would upset the delicate balance of power between free states and slave states.