20th century map depicting the USSR and China's east coasts and the west coast of USA and Canada.
The Cold War was a conflict between the United States of America and the Soviet Union (Russia) and their respective allies. It was a persistent state of high tension between the two largest military and economic powers on Earth during the the second half of 20th century.
As the two dominant nation-states to emerge after World War II the United States of America (USA) and the Union of Soviet Socialist Republics (USSR) were diametrically opposed in economic and social philosophy. However, the devastating effects of that conflict combined with the enormous nuclear arsenal of the two countries made open hostilities a disastrous prospect for both. Rather than risk mutual annihilation the two powers engaged in a "cold war" that consisted of intense espionage, political manipulation of satellite states, and covert military actions.
The atmosphere created by the Cold War put enormous strains on the governments and citizens of both countries. Suspicion of each other's motives was the normal state of affairs, and the military leadership of both sides regularly argued for armed conflict.
The Cold War on Earth during this time was in many ways a predecessor to the interstellar Federation-Klingon Cold War of the 23rd Century.
When Quark, Rom, Nog, and Odo were thrown back in time to 1947 the military of the US accused them of being involved with the Russians, their Cold War adversary. After the US was on the verge of rejecting Quark's deal, the Ferengi threatened to sell 24th century technology to the Soviets. (DS9: "Little Green Men")
Julian Bashir's holosuite program Julian Bashir, Secret Agent was set during the 1960s at the height of the Cold War. (DS9: "Our Man Bashir")
The Cold War was ended in 1991 when the Soviet Union, driven to social and economic hardship by extensive military spending, was dissolved. (VOY: "Future's End, Part I")
Background Information
The end of the Cold War was the inspiration for Star Trek VI: The Undiscovered Country. Star Trek: The Next Generation did not envisage the end of the Cold War or the Soviet Union as demonstrated by the reference to the Baikonur Cosmodrome in "The Naked Now."
Likewise, the collapse of the Soviet Union between the release Star Trek IV: The Voyage Home and Star Trek VI created the apocrphya of having an officer at Starfleet Headquarters refer to the city of Leningrad, which after the fall of the USSR reverted to its original name of St. Petersburg.
The character of Pavel Chekov in Star Trek: The Original Series was a controversial move, coming as it did at the height of the Cold War, only six years after the construction of the Berlin Wall and five years after the Cuban Missile Crisis.
Template:Earthwars