How did lessons learned from world war ii influence president truman’s decision to send troops to aid south korea after north korea invaded?

One of the main ways in which lessons learned from World War II influence President Truman’s decision to send troops to aid South Korea after North Korea invaded was that World War II showed that inaction after a country violated the sovereign rights of another could lead to a prolonged conflict. 

No , abraham lincoln is elected 16th president of the united states over a deeply divided democratic party, becoming the first republican to win the presidency . lincoln receive 40 % of the popular vote handily defeated three other candidates