"The Four Policemen" was a term coined by U.S. President

President of the United States

The President of the United States of America is the head of state and head of government of the United States. The president leads the executive branch of the federal government and is the commander-in-chief of the United States Armed Forces....

 Franklin D. Roosevelt

Franklin D. Roosevelt

Franklin Delano Roosevelt , also known by his initials, FDR, was the 32nd President of the United States and a central figure in world events during the mid-20th century, leading the United States during a time of worldwide economic crisis and world war...

, to refer to four major Allies of World War II

Allies of World War II

The Allies of World War II were the countries that opposed the Axis powers during the Second World War . Former Axis states contributing to the Allied victory are not considered Allied states...

 and founders of the United Nations

United Nations

The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 (UN): the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

, Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

, and China

Republic of China

The Republic of China , commonly known as Taiwan , is a unitary sovereign state located in East Asia. Originally based in mainland China, the Republic of China currently governs the island of Taiwan , which forms over 99% of its current territory, as well as Penghu, Kinmen, Matsu and other minor...

.

Roosevelt's phrase symbolized his conception of the post-World War II world, though the idea would not come to fruition until the establishment of the UN, which emerged following the Declaration by United Nations

Declaration by United Nations

The Declaration by United Nations was a World War II document agreed to on January 1, 1942 during the Arcadia Conference by 26 governments: the Allied "Big Four" , nine American allies in Central America and the Caribbean, the four British Dominions, British India, and eight Allied...

 of January 1, 1942. In the words of a former Undersecretary General of the UN, Sir Brian Urquhart

Brian Urquhart

Sir Brian Urquhart, KCMG, MBE is a former Undersecretary-General of the United Nations. He is also a World War II veteran and an author.-Early life:...

:
Each of the Four Policemen was to maintain order in its respective sphere: Britain in its empire and in Western Europe; the Soviet Union in Eastern Europe and the central Eurasian landmass; China in East Asia and the Western Pacific; and the United States in the Western Hemisphere.
Given the weakness of the government of Chiang Kai-shek, President Franklin D. Roosevelt foresaw the United States dominating China's sphere of influence. Thus, in effect, the United States would run two spheres and thereby maintain global supremacy over a declining Britain and a Soviet Union badly damaged by the Second World War.