After the Texas War for Independence, why did northerners oppose the annexation of Texas?

Responses

They believed the United States was becoming too large to govern effectively.
They believed the United States was becoming too large to govern effectively.

They feared it would draw the United States into a war with Mexico.
They feared it would draw the United States into a war with Mexico.

They did not want to upset the balance of free and slave states in Congress.
They did not want to upset the balance of free and slave states in Congress.

They did not believe people living in Texas had a legitimate claim to the land.

They were concerned about the potential spread of slavery into new territories.