Tariffs can help domestics producers but can hurt consumers. Governments impose tariffs on imported goods and services to make them more expensive to consumers. Tariff provides revenue to the government and give a price advantage to domestic producers. While it protects domestic industries, it can also hurt foreign producers.
The United States historically had far less imperial actions in comparison to their European counterparts. The United States did not have massive colonial empires like Britain or France. The United States acquired some territories outside of the "continental" US however, it did not maintain an imperial presence like any of its European cohorts.
Industrialization in the north caused the civil war. The industrial revolution in the North, during the first few decades of the 19th century, brought about a machine age economy that relied on wage laborers, not slaves. I hope that this is the answer that you were looking for and it has helped you.
