Columbia subject headings:
Foreign trade regulation--United States.
Protectionism--United States.
Steel industry and trade--United States.
Tariff on steel--United States.
United States--Economic conditions--2001-
Harvard subject headings:
Foreign trade regulation--United States.
Protectionism--United States.
Steel industry and trade--United States
Tariff on steel--United States.
United States--Economic conditions--2001-2009.
Princeton subject headings:
Foreign trade regulation--United States.
Protectionism--United States.
Steel industry and trade--United States.
Tariff on steel--United States.
United States--Economic conditions--2001-2009.