Columbia subject headings:
United States--Foreign relations--21st century.
United States--Politics and government--21st century.
World politics--21st century.
Harvard subject headings:
United States--Foreign relations--21st century.
United States--Politics and government--21st century.
World politics--21st century.
Princeton subject headings:
United States--Foreign relations--21st century.
United States--Politics and government--21st century.
World politics--21st century.