There was great tension between pro-slavery and anti-slavery representatives over how new territories won would handle the issue of slavery.
The Mexican-American War and the 1848 Treaty of Guadalupe Hidalgo, forced onto the remnant Mexican government, drew some criticism in the U.S. for their casualties, monetary cost, and heavy-handedness. Furthermore, the question of how to treat the new acquisitions also intensified the debate over slavery and in many ways inflamed it, as potential westward expansion of the institution took an increasingly central and heated theme in national debates preceding the American Civil War.
They did want to be imperial
Many primary civilizations started in river valleys because for the cities in each civilization an important portion of the population existed in cities. Large-scale farming was a requirement to feed the large populations. Fertile due to flooding the land by rivers was home to lush plant life and an outstanding place to plant and grow crops. The close source of water permitted for irrigation for the large-scale farming as well as drinking and bathing. Water also intended animals and animals meant food so this was another advantage to settling in river valleys. Settling and living in river valleys later main to further development of civilizations and new patterns of living such as trade and communication by means of the river for transportation.
Answer:
A particularly severe panic in 1907 resulted in bank runs that wreaked havoc on the fragile banking system.
