to what extent did the acquisition of new territories hurt and help the US

The acquisition of new lands in some degree helped the United States economy, but it hurt the union of the republic and was a cause of the Civil War, because it made the dispute over slavery even more prominent.
When the Louisiana territory was added onto the United States it provided more land for Westward expansion and it enabled farmers to build up a strong agricultural economy there. The ability to gain new land in the West also attracted many immigrants from Europe, who were a big working force in the American industry. Also through railroads and canals raw materials produced in the West could be transported to the Northeast and there be manufactured into goods that could be sold or even exported. However, the new territories had to be divided up into states and the decision of whether they should be slave or free states had to be made. This caused tensions and was only temporarily solved with the Missouri Compromise. The additional territory that would be gained with Texas would hurt the union, because it was enforcing slavery and it would be enlarging American slavery. This loss of balance would later cause for the United States to engage in the Civil War.