Columbia subject headings:
Environmental policy--United States.
Global environmental change--Political aspects--United States.
Natural resources--Government policy--United States.
Strategic materials--Government policy--United States.
United States--Foreign economic relations--21st century.
United States--Foreign relations--21st century.
World politics--21st century.
Harvard subject headings:
Environmental policy--United States
Global environmental change--Political aspects--United States.
Natural resources--Government policy--United States
United States--Foreign relations.
Princeton subject headings:
Environmental policy--United States.
Global environmental change--Political aspects--United States.
Natural resources--Government policy--United States.
United States--Foreign relations.