The Missouri Compromise of 1820 involved land gained from the Louisiana Purchase. The Louisiana Purchase was the purchase of land from France in 1803 that consisted of over 530 million acres.
The growth of the empire continued to increase their confidence.
What gave them an advantage is economic prosperity due to rich soil and development of plantations based on slave labor. Many profit was accumulated from crops (tobacco) and also cotton. Later on in the 1800s when Eli Whitney created the cotton gin it created a boom in the slave industry and increased largely by 71%. After that the tool allowed mass production in textile industries.
