America was growing rapidly from 1800-1850, with the Louisiana Purchase and Mexican cessions. These expansions had a large impact on national unity. The question of slavery in new territories caused national disunity; however as the nation expanded in areas not suitable for slavery, unity was much stronger.
The Louisiana Purchase, of 1803, had a positive effect on national unity. Acquiring this land was very important, because with the land came New Orleans and thus the mouth of the Mississippi. In fact, it was the expectation that only New Orleans would be bought, however all of the Louisiana Territory was offered. This was a huge piece of land, almost one-third of the country. Most Americans were thrilled because now these new western lands were theirs to exploit.
With the new lands, states were bound to form; however problems between the North and South did arise. When Missouri issued for statehood in 1820, there was controversy on whether it would be a free state or slave state.
Northerners largest complaint was that if more slave states entered the union, the north would be outnumbered by the south in Congress. But a compromise was reached, the Missouri Compromise. This stated everything above 36 < 30` of the Louisiana Purchase would stay free, and everything below, slave. Although the South was thrilled with it, the compromise did not settle all sectional conflicts. In fact, some northern legislators refused to accept the compromise all together, and thus debates over issue continued. The Missouri Compromise, brought out strong feelings on either side, and national unity suffered thereafter.
Expansion in areas where slavery was not suitable, such as way up north, there were no sectional conflicts. There was very little controversy with the admittance of Maine, even though it became a state in the same year...