Answer: Gunboat Diplomacy.
Explanation: This is when a nation uses the threat of force or conspicuous displays of firepower to have influence in foreign policy, and it's called "Gunboat Diplomacy". The president Roosevelt used this tactic as a way to secure Panama's independence from Colombia; in a way of exchange the United States was able to secure access to what would become the Panama Canal.
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Sectionalism became very tensed in the late 1940s because of the separation of the North and the South because of the slavery. People in the North were focusing on industrializing, urbanizing, and building factories while the people from the South concentrated in agriculture. The Southerners was claiming that the North's factories weren't treating everyone fairly and lead into a war.
Yes, that's in fact true.
