What did the Missouri Compromise of 1820 do?

It took lands from Mexico in the Southwest.
It annexed Texas as part of the United States.
It abolished slavery in Mexico.
It made slavery illegal in new states north of the 36th parallel.

The correct answer is: It made slavery illegal in new states north of the 36th parallel.

Why did the Republic of Texas have trouble joining the United States?

The Republic of Texas faced several challenges and obstacles in its attempt to join the United States. Some of the reasons for the difficulties include:

1. Slavery: One major obstacle was the issue of slavery. Texas was a slave state, and its annexation would upset the balance between free and slave states in Congress. Many Northern politicians opposed the annexation of Texas due to concerns about the expansion of slavery.

2. Border disputes: Texas claimed a border that extended as far as the Rio Grande, while Mexico considered the Nueces River as the boundary. This led to ongoing border conflicts and tensions between Mexico and the Republic of Texas. The United States did not want to be dragged into a potential war with Mexico by annexing Texas.

3. Fear of war with Mexico: Annexing Texas would likely provoke Mexico, which had not recognized Texas' independence. The United States was hesitant to engage in any military conflicts with Mexico.

4. Political divisions: There were divisions within the United States government and society regarding the annexation of Texas. Some politicians supported annexation, while others were against it. This created political strife and disagreements within the United States.

5. Public opinion: Many Northern states were opposed to the annexation of Texas due to concerns about the expansion of slavery. There was significant opposition from anti-slavery activists and abolitionist groups.

It was not until 1845, when James K. Polk became president and pushed for the annexation of Texas, that the Republic of Texas finally joined the United States as the 28th state.