On March 1, the U.S. and global business communities, their financial markets, the U.S. Congress and many in the Trump Cabinet and White House were surprised to learn that the President was considering the imposition of tariffs on imported steel and aluminum. Initial response to the tariffs by many in Congress and even within the Cabinet has been negative.
In modern times the U.S. has operated within the umbrella of open-trade/low-tariff policies. However, the U.S. has a long history of tariffs going back to when it was a fledgling nation. The first tariff law passed by Congress, the Tariff of 1789, was enacted on virtually all foreign goods coming into the U.S. The idea was to protect emerging domestic industries and to raise money to run the government and (already) service its debt. The fact is that until the federal income tax was initiated in 1913, revenues from protectionist trade policies were keystones of American foreign policy and one of the greatest sources of government revenue. During the World War I years, tariffs generated about 30% of federal income, but tariff income became a declining percentage of revenues since 1935.