Tariffs have long been used globally to support local industries by incentivizing citizens to purchase domestically made products. At the turn of the 20th century, tariffs were the primary source of tax revenue for many nations. Today, funding comes from income, payroll and corporate taxes. In the U.S., tariffs accounted for approximately 90% of federal income until the Civil War. After World War II, tariffs fell out of favor in developed economies because they often led to reduced trade, higher prices and retaliation from abroad.