After the civil war, railroads connected the country on a national scale, boosting the economy and leading to mass production, mass consumption, and encouraging entrepreneurs.
Some risks of having different idea within your peers can be judgment. If someone’s idea is contrasting with yours it can make you seem crazy or unknowing.
McKinley's foreign policy centered on imperialism with the mission of bringing American culture to the conquered areas.
Jingoism is extreme patriotism which grew in the US following the Civil War and Industrialization. To become a modern country, the US came to believe they must engage in imperialism.
During McKinley's presidency, the US went to war with Spain in Cuba and annexed Hawaii. The gaining of new lands brought into the US empire were done so with the mission to spread democracy. McKinley argued the US had an obligation to support and spread democratic ideology. The extreme patriotism of the US supported these actions by believing the US was the best country and could be a model for other countries.