Question: When was the oldest US President in office elected?

full_context: Document 1: List of presidents of the United States by age: The oldest living U.S. president is George H.W. Bush, born June 12, 1924 (age 93 years, 346 days). On November 25, 2017, he also became the longest - lived president, surpassing the lifespan of Gerald Ford, who died at the age of 93 years, 165 days. The second oldest living president, Jimmy Carter, has the distinction of having the longest post-presidency in U.S. history, currently at 37 years, 124 days. He surpassed the previous record, held by Herbert Hoover (31 years, 230 days) on September 7, 2012. The youngest living president is Barack Obama, born August 4, 1961 (age 56 years, 293 days).
Document 2: Soviet Union: The Soviet Union suffered greatly in the war, losing around 27 million people. Approximately 2.8 million Soviet POWs died of starvation, mistreatment, or executions in just eight months of 1941 -- 42. During the war, the Soviet Union together with the United States, the United Kingdom and China were considered as the Big Four of Allied powers in World War II and later became the Four Policemen which was the foundation of the United Nations Security Council. It emerged as a superpower in the post-war period. Once denied diplomatic recognition by the Western world, the Soviet Union had official relations with practically every nation by the late 1940s. A member of the United Nations at its foundation in 1945, the Soviet Union became one of the five permanent members of the United Nations Security Council, which gave it the right to veto any of its resolutions.
Document 3: History of Russia: U.S.–Soviet relations deteriorated following the beginning of the nine-year Soviet–Afghan War in 1979 and the 1980 election of Ronald Reagan, a staunch anti-communist, but improved as the communist bloc started to unravel in the late 1980s. With the collapse of the Soviet Union in 1991, Russia lost the superpower status that it had won in the Second World War.
Document 4: List of presidents of the United States by age: The oldest living U.S. president is George H.W. Bush, born June 12, 1924 (age 93 years, 261 days). On November 25, 2017, he also became the longest - lived president, surpassing the lifespan of Gerald Ford, who died at the age of 93 years, 165 days. The second oldest living president, Jimmy Carter, has the distinction of having the longest post-presidency in U.S. history, currently at 37 years, 39 days. He surpassed the previous record, held by Herbert Hoover (31 years, 230 days) on September 7, 2012. The youngest living president is Barack Obama, born August 4, 1961 (age 56 years, 208 days).
Document 5: List of presidents of the United States by age: The median age upon accession to the presidency is 55 years and 3 months. This is how old Lyndon B. Johnson was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of 42 years, 322 days, following William McKinley's assassination; the oldest was Donald Trump, who was 70 years, 220 days old at his inauguration. The youngest person to be elected president was John F. Kennedy, at 43 years, 163 days of age on election day; the oldest was Ronald Reagan, who was 73 years, 274 days old at the time of his election to a second term.
Document 6: List of presidents of the United States by age: The median age upon accession to the presidency is roughly 55 years and 6 months, which is about how old Benjamin Harrison was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president following William McKinley's assassination, at the age of 7004156620000000000 ♠ 42 years, 322 days. The youngest person elected president was John F. Kennedy, who was inaugurated into office at the age of 7004159420000000000 ♠ 43 years, 236 days. Assassinated three years into his term, he became the youngest at the time of leaving office (7004169780000000000 ♠ 46 years, 177 days); the youngest person at the time of leaving office after serving a full four - year term was Theodore Roosevelt (7004183900000000000 ♠ 50 years, 128 days). The oldest person at the time of entering office was Donald Trump, at the age of 7004257880000000000 ♠ 70 years, 220 days; Ronald Reagan was the oldest person in office, at the age of 7004284730000000000 ♠ 77 years, 349 days when his presidency ended in January 1989.
Document 7: List of presidents of the United States by age: The median age at accession to the presidency is roughly 55 years and 6 months, which is about how old Benjamin Harrison was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president following William McKinley's assassination, at the age of 7004156620000000000 ♠ 42 years, 322 days. The youngest person elected president was John F. Kennedy, who was inaugurated into office at the age of 7004159420000000000 ♠ 43 years, 236 days. Assassinated three years into his term, he became the youngest at the time of leaving office (7004169780000000000 ♠ 46 years, 177 days); the youngest person at the time of leaving office after serving a full four - year term was Theodore Roosevelt (7004183900000000000 ♠ 50 years, 128 days). The oldest person at the time of entering office was Donald Trump, at the age of 7004257880000000000 ♠ 70 years, 220 days; Ronald Reagan was the oldest person in office, at the age of 7004284730000000000 ♠ 77 years, 349 days when his presidency ended in January 1989.
Document 8: Russian Soviet Federative Socialist Republic: In 1964, Nikita Khrushchev was removed from his position of power and replaced with Leonid Brezhnev. Under his rule, the Russian SFSR and the rest of the Soviet Union went through an era of stagnation. Even after he died in 1982, the era didn’t end until Mikhail Gorbachev took power and introduced liberal reforms in Soviet society.
Document 9: Nuclear arms race: Throughout the 1970s, both the Soviet Union and United States replaced old missiles and warheads with newer, more powerful and effective ones. This continued to worsen Soviet - U.S relations. On June 18, 1979, the SALT II treaty was signed in Vienna. This treaty limited both sides' nuclear arsenals and technology. However, this treaty as well as the era of the détente ended with the Soviet Union's invasion of Afghanistan in January, 1980. The United States once again significantly increased military and nuclear spending, while the Soviets were unable to respond and continued to pursue the détente.
Document 10: Cold War: By the 1970s, both sides had become interested in making accommodations in order to create a more stable and predictable international system, inaugurating a period of détente that saw Strategic Arms Limitation Talks and the US opening relations with the People's Republic of China as a strategic counterweight to the Soviet Union. Détente collapsed at the end of the decade with the beginning of the Soviet -- Afghan War in 1979. The early 1980s were another period of elevated tension, with the Soviet downing of Korean Air Lines Flight 007 (1983), and the ``Able Archer ''NATO military exercises (1983). The United States increased diplomatic, military, and economic pressures on the Soviet Union, at a time when the communist state was already suffering from economic stagnation. In the mid-1980s, the new Soviet leader Mikhail Gorbachev introduced the liberalizing reforms of perestroika (`` reorganization'', 1987) and glasnost (``openness '', c. 1985) and ended Soviet involvement in Afghanistan. Pressures for national independence grew stronger in Eastern Europe, especially Poland. Gorbachev meanwhile refused to use Soviet troops to bolster the faltering Warsaw Pact regimes as had occurred in the past. The result in 1989 was a wave of revolutions that peacefully (with the exception of the Romanian Revolution) overthrew all of the communist regimes of Central and Eastern Europe. The Communist Party of the Soviet Union itself lost control and was banned following an abortive coup attempt in August 1991. This in turn led to the formal dissolution of the USSR in December 1991 and the collapse of communist regimes in other countries such as Mongolia, Cambodia and South Yemen. The United States remained as the world's only superpower.
Document 11: Soviet Union–United States relations: The relations between the United States of America and the Union of Soviet Socialist Republics (1922 -- 1991) succeeded the previous relations from 1776 to 1917 and predate today's relations that began in 1992. Full diplomatic relations between the two countries were established late due to mutual hostility. During World War II, the two countries were briefly allies. At the end of the war, the first signs of post-war mistrust and hostility began to appear between the two countries, escalating into the Cold War; a period of tense hostile relations, with periods of détente.
Document 12: Soviet–Afghan War: The Soviet -- Afghan War lasted over nine years, from December 1979 to February 1989. Insurgent groups known as the mujahideen fought against the Soviet Army and the Democratic Republic of Afghanistan government, mostly in the country's rural countryside. The mujahideen groups were backed by the United States and Pakistan, making it a Cold War proxy war. Between 562,000 and 2,000,000 civilians were killed and millions of Afghans fled the country as refugees, mostly to Pakistan and Iran.
Document 13: List of presidents of the United States by age: Assassinated three years into his term, John F. Kennedy was the youngest at the time of leaving office (46 years, 177 days); the youngest president to leave office at the conclusion of a normal transition was Theodore Roosevelt (50 years, 128 days). The oldest at the time of leaving office was Ronald Reagan (77 years, 349 days).
Document 14: Soviet Union: With the rise of strong nationalist and separatist movements inside the union republics, Gorbachev tried to avert a dissolution of the Soviet Union in the post-Cold War era. A March 1991 referendum, boycotted by some republics, resulted in a majority of participating citizens voting in favor of preserving the union as a renewed federation. Gorbachev's power was greatly diminished after Russian President Boris Yeltsin played a high - profile role in facing down an abortive August 1991 coup d'état attempted by Communist Party hardliners. On 25 December 1991, Gorbachev resigned and the remaining twelve constituent republics emerged as independent post-Soviet states. The Russian Federation -- formerly the Russian SFSR -- assumed the Soviet Union's rights and obligations and is recognized as the successor state of the Soviet Union. In summing up the international ramifications of these events, Vladislav Zubok stated: ``The collapse of the Soviet empire was an event of epochal geopolitical, military, ideological and economic significance. ''
Document 15: List of presidents of the United States by age: The median age upon accession to the presidency is roughly 55 years and 6 months, which is about how old Benjamin Harrison was at the time of his inauguration. The youngest person to assume the office was Theodore Roosevelt, who became president at the age of 7004156620000000000 ♠ 42 years, 322 days, following William McKinley's assassination. The youngest person elected president was John F. Kennedy, who was inaugurated into office at the age of 7004159420000000000 ♠ 43 years, 236 days. Assassinated three years into his term, he became the youngest at the time of leaving office (7004169780000000000 ♠ 46 years, 177 days); the youngest person at the time of leaving office after serving a full four - year term was Theodore Roosevelt (7004183900000000000 ♠ 50 years, 128 days). The oldest person at the time of entering office was Donald Trump, at the age of 7004257880000000000 ♠ 70 years, 220 days; Ronald Reagan was the oldest person in office, at the age of 7004284730000000000 ♠ 77 years, 349 days when his presidency ended in January 1989.
ground_truth: 1980
sub_queries: who was the oldest us president in office Answer: Ronald Reagan
When was Ronald Reagan elected? Answer: 1980