- "Washington, D.C. The year is 1986. We've landed at the height of the Cold War in a world poised for nuclear annihilation."
- —Rip Hunter on the height of Cold War
The Cold War was a conflict in the 20th century of Earth One timeline. The scope of the conflict included such opposing powers as the United States and the Soviet Union. The height of the conflict was in 1986. Vandal Savage and the time-traveling members of Rip Hunter's team tried to influence the conflict, with Savage seeking to ignite it into a state of full-out global war, while Rip Hunter and his crew were trying to keep history more or less intact.
The Cold War was a legacy of the earlier World War II. According to Dr. Valentina Vostok, the Soviet Union's goal was to rise ever stronger and defeat the United States, just like it has arisen from the ashes when the Nazis invaded.
Although the Justice Society of America members like Amaya Jiwe thought that fighting Adolf Hitler would unite the U.S. and the Soviet Union, the two powers ultimately ended up in a world-spanning rivalry called the Cold War. As USA's friendship with the Soviet Union ended, the Justice Society continued fighting as what was known as the "Iron Curtain" descended over Central and Eastern Europe. A diplomatic cable from 1956 from the British ambassador warned the JSA about Soviet spies in their midst, leading to President Eisenhower suspecting Todd Rice/Obsidian as the traitor, a suspicion likely biased due to prejudice towards Rice's homosexuality. The team, lacking Rice, was sent into Leipzig, Germany, now under Soviet military control, on a secret mission. They never made it back.
Vandal Savage, after learning about the existence of the meta-human Firestorm in 1975, spent years researching it from what little information he had. According to the Pentagon, by 1986, Savage defected to the Soviet Union, relaying his research of the Firestorm Matrix to Dr. Vostok. Thanks to Savage's influence, Vostok was able to start "Operation Svarog", the goal of which was the creation of a Soviet Firestorm, which would allow the Soviet Union to defeat the United States (Earth One) once and for all, winning the Cold War by "igniting" it.
After a time-traveling Martin Stein, the leader of the original F.I.R.E.S.T.O.R.M. project, was arrested by Mikhail Arkadin and brought to Dr. Vostok, Rip Hunter was informed by Gideon that a version of the future, in which Soviet Firestorm-like meta-humans would destroy Star City by the year 2003, was cementing. Rip Hunter's team managed to stop Vandal Savage and Valentina Vostok, who died in a nuclear explosion at Koshmar prison grounds, saving their imprisoned members and preventing a Soviet victory in the Cold War.
On December 8th, 1987, the Soviet Union's Mikhail Gorbachev and the United States' Ronald Reagan signed the INF Treaty, reducing both countries' nuclear arsenals and paving the way for the end of the Cold War. Reagan and Gorbachev were among the targets in a historical aberration plot overseen by Damien Darhk and Eobard Thawne, which ended up prevented by the Legends. The Soviet Union's opportunistic KGB agents also took part in the plot, trying to have Damien Darhk, who infiltrated the White House administration beforehand, to hand over the USA's nuclear codes and kill the two nation leaders, in exchange for a certain artifact that Darhk was after. The KGB agents were ultimately murdered by Darhk and his Ghosts. 
The Cold War eventually came to an end, with the United States surviving as a unified country. The Soviet Union, however, collapsed in the year 1991, with its failing economy and crumbling empire. By 2016, the Soviet successor state, Russia, was ruled by criminals and crooked politicians, desperate to hang on to power and divide the riches amongst their cronies. The Cold War was a subject of historical study decades later. In 2017, Clifford DeVoe held a lecture on the effects of the event, and specifically Ronald Reagan's administration.
DC's Legends of Tomorrow
- "Therefore I Am" (mentioned)
- Valentina Vostok cited such things as the signs of the United States' weakness during the Cold War: Big Mac, MTV, movie-star president.
Behind the scenes
- The Cold War was a historical conflict that represented political and military tension after World War II between powers in the Western Bloc (the United States of America, its NATO allies and others) and powers in the Eastern Bloc (the Soviet Union and its Warsaw Pact allies). The term "cold" is used because there was no large-scale fighting directly between the two sides, although there were major regional wars, known as "proxy wars", supported by the great powers.
- In the DC comics, the Cold War was a long event that would span the rise of many superhero careers of the New Earth continuity.