He had an approval rating of 53 per cent in a poll conducted two months earlier. Truman was expected to lose the general election to Thomas Dewey, a Republican, but he pulled off a narrow victory.

Truman announced on March 29, 1952, that he would not seek a second full term after losing in the New Hampshire primary to Senator Estes Kefauver of Tennessee. His approval rating had sunk to 22 per cent amid economic trouble and the Korean war.

Dwight Eisenhower

Eisenhower, a Republican, had an approval rating of 75 per cent shortly before he announced his re-election campaign on February 29, 1956. He had suffered a heart attack months earlier at age 64, leading to questions over whether he would run.

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As the former supreme allied commander during World War II, Eisenhower convinced Americans that he was the right leader on the world stage. He defeated Democratic candidate Adlai Stevenson.

John F. Kennedy

Kennedy was assassinated in 1963, before he had a chance to run for a second term.

Lyndon B. Johnson

Johnson was vice-president at the time of Kennedy’s death, and he swiftly ran for his first full term in 1964, winning a landslide victory over Republican Barry Goldwater. However, the Democrat’s popularity slipped badly over the Vietnam war and domestic turmoil.

It became clear that Johnson was at risk of losing his party’s nomination in 1968 after Eugene McCarthy’s strong showing in the New Hampshire primary. Soon after, Johnson shocked the country by announcing on March 31, 1968, that he would not seek a second term. His approval rating was only 36 per cent that month.

Richard Nixon

Nixon had an approval rating of 50 per cent when he announced his re-election campaign on January 7, 1972. The Watergate break-in at the Democratic National Committee headquarters occurred that summer, but the scandal didn’t gain enough momentum to drag him down.

Nixon, a Republican, defeated George McGovern, a Democrat, in a landslide. However, he would not finish his second term, resigning in 1974 after revelations about Watergate caught up with him.

Gerald Ford

Ford, a Republican, became president when Nixon stepped down, and he announced that he would run for a full term of his own on July 8, 1975. He had a 52 per cent approval rating the month before.

He faced discontent over inflation and controversy from his decision to pardon Nixon, and he lost the election to Jimmy Carter, a Democrat.

Jimmy Carter

Carter announced his re-election campaign on December 4, 1979. His approval rating had just hit 51 per cent. However, the American people had grown weary of inflation, an energy crisis and a hostage crisis in Iran. Carter was wounded by a primary challenge from Senator Ted Kennedy, and he was ultimately defeated by Ronald Reagan, a Republican.

Ronald Reagan

Reagan announced his re-election bid on January 29, 1984. His approval rating was 52 per cent that month. Despite concerns about his age – he was 73 and the oldest president in history at the time – Reagan handily defeated Walter Mondale, a Democrat.

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George H.W. Bush

Bush’s popularity skyrocketed after the Gulf War, when US forces pushed Iraq out of Kuwait. However, his approval rating had subsided to 65 per cent by the time he announced his re-election campaign on October 11, 1991.

Pat Buchanan challenged Bush in the Republican primary. Although Bush won the nomination, his shot at a second term dimmed amid an economic downturn. He ultimately lost to Bill Clinton, a Democrat.

Bill Clinton

Clinton’s approval rating was 47 per cent when he announced that he would run for re-election on April 14, 1995. Democrats had suffered a wipeout midterm election in 1994, leading some to question whether Clinton would be a one-term president. But he rebounded with the help of a growing economy, and he defeated Bob Dole, a Republican.

George W. Bush

The September 11 attacks of 2001 led Bush, a Republican, to invade Afghanistan, followed by another war in Iraq. One month after US forces entered Baghdad, Bush announced he would run for re-election on May 16, 2003. His approval rating was 69 per cent that month. He defeated John Kerry, a Democrat.

Barack Obama

Obama, a Democrat, had a 48 per cent approval rating when he announced his re-election campaign on April 4, 2011. He struggled to convince Americans that the economy was improving after the financial collapse and subsequent recession, but he ultimately defeated Mitt Romney, a Republican.

Donald Trump

Trump, a Republican, announced that he would run for re-election on June 18, 2019. The previous month, his approval rating was 41 per cent. He was impeached for the first time at the end of the year, and then the coronavirus pandemic stalled the economy. Joe Biden, a Democrat, defeated Trump, who tried to prevent the peaceful transfer of power.

Joe Biden

Biden announced his re-election campaign on April 25. His approval rating was 40 per cent the previous month. Biden would be 86 at the end of a second term, leading to fears that he’s too old to keep such a demanding job.

However, Biden has not drawn any significant primary challengers. The only Democrats running are Marianne Williamson and Robert F. Kennedy Jnr. Meanwhile, Trump is leading in Republican primary polls as he seeks the party’s nomination, raising the potential for a rematch with Biden.