To run a country you need a lot of things: leadership, support from the people. But, crucially, you also need to be pretty smart. While there is a long-running debate about the accuracy of IQ to determine intelligence, and whether you can apply it to historical figures, it's also pretty fun to figure out which U.S. presidents might have been smarter than others. It should be noted that 100 is an "average" IQ; the vast majority of presidents rank above this, which should come as a relief, considering they ran our country! Check out our rankings, which we got from a 2006 American Psychology report.

Donald Trump (145 or 101)

Whether you like his politics or not, Donald Trump has, during his tenure, has shown an... interesting manner of speaking which some have identified as being similar to the early stages of dementia. Different reports list Trump's IQ at 101 — just above average — and 145.

Ulysses S. Grant (110)

A forefront Civil War-era general and the 18th President of the US, Grant studied at West Point Military School. As president, he was known to be concerned about the plight of African Americans in the Reconstruction Era.

Andrew Johnson (110)

Andrew Johnson, the 17th President of the U.S., is not looked on kindly by historians. He was the first president to be impeached by Congress and was widely criticized for restoring the Confederate to the Union without protecting former slaves.

William Taft (114)

Taft studied at Cincinnati Law School before starting a long legal career that ended in him becoming a Chief Justice. He continued Theodore Roosevelt's anti-trust laws but eventually split from Roosevelt. He lost the election to Wilson in 1913.

Calvin Coolidge (124)

Coolidge was educated in law at Amherst College. His predecessor, Warren G. Harding, had a tenure spoiled by scandals, but Coolidge worked hard to restore the faith of the American people in the Presidency.

Harry S. Truman (130)

Truman, who gained the office after the death of the immensely popular Franklin D. Roosevelt, lead America into the post-war era. He set huge precedents for the modern world, including the UN, NATO, and the Truman Doctrine.

Zachary Taylor (129)

One of the lesser-known U.S. Presidents, Zachary Taylor had the shortest reign. He died of a stomach illness just 16 days after becoming President. Before this, he was a well-known general who fought in the Mexican-American War.

James Buchanan (129)

Buchanan is a very unpopular president. Because of his perceived sympathies with the south, his actions as President of the United States are blamed for starting the Civil War, which started just two months after his successor took office.

Warren G. Harding (130)

Harding promised to return the U.S. to the "normalcy" of the pre-WWI era. He was successful and popular, but following his death, it became public that he was a part of several high-profile scandals.

James K. Polk (130)

Polk was a pro-slavery president, serving from 1845 to 1849. He also won the Mexican-American War while added swaths of territory to the US, like Arizona, New Mexico, and Nevada.

Ronald Reagan (130)

Reagan was, famously, an actor before becoming Governor of California and later President. His "Reaganomic" economic policies and "War on Drugs," while controversial, were signatures of his reign.

William Henry Harrison (132)

Harrison was a general who was successful in the Northwest Indian War and the War of 1812. He would have likely been a pro-slavery president, but he died 30 days into his Presidency and was succeeded by Tyler.

William McKinley (132)

While the beginning of McKinley's term was eventful — he started and won the Spanish-American War and annexed Hawaii into the US — he was assassinated by the anarchist Leon Czolgosz in 1901. Roosevelt, the successor, quickly overshadowed McKinley.

Martin van Buren (133)

Van Buren was, before becoming president, a lawyer and Ambassador to the United Kingdom. He was an abolitionist, and vetoed Texas's entry to the Union to prevent the country from becoming too pro-slavery.

Richard Nixon (133)

Richard Nixon studied law at Duke University. He has a controversial history, though he took America to the moon and won a landslide in 1972, but was forced to resign in 1974 when it was clear he would be removed from office.

Dwight D. Eisenhower (134)

Eisenhower was a World War Two general who was educated at West Point. He presided over key events of the early Cold War, like the Korean War, the First Indochina War, and the Hungarian Revolution.

John Tyler (136)

John Tyler was the Tenth President of the United States. He was a defender of state's rights and was a strict constitutionalist. He had very little impact as a whole and is not well regarded by American historians.

James Monroe (138)

Monroe was a Founding Father and the fifth President of the United States. His most lasting achievement was the Monroe Doctrine, which opposed further colonisation of the Americas by European powers.

George W. Bush (138)

Despite his reputation for being unintelligent, George W. Bush was well-educated, having graduated from Yale. His most lasting legacies were the Iraq War and the 2008 Financial Crisis, which give him a poor ranking in Presidential surveys.

Gerald Ford (140)

Ford became President following the resignation of Nixon who, controversially, Ford pardoned. In his two-year term he had extraordinarily bad luck in the economy and saw the collapse of the U.S. war in Vietnam.

George Washington (140)

The first and by far the most famous U.S. President, Washington was a general in the Revolutionary War and set huge precedents that still stand to this day. He was not formally educated, but learned mathematics and history at home.

Lyndon B. Johnson (140)

The immediate successor following JFK's assassination, Lyndon is best known for escalating the war in Vietnam and his Great Society reforms, which lifted many out of poverty and improved public services.

Abraham Lincoln (140)

Abraham Lincoln is famous for leading the U.S. through the majority of the American Civil War. He is beloved for his strong anti-slavery stance and is generally seen as the president who "freed the slaves."

Herbert Hoover (141)

Hoover was a promising president who had a very energetic career in the U.S. cabinet before rising to the top office in 1928. Unfortunately for Hoover, a year later the Wall Street Stock Market crashed, starting the Great Depression.

James A. Garfield (141)

Garfield was a fierce advocate for African Americans post-Civil War, cutting corruption in the U.S. Senate and enhancing Presidential power. Unfortunately, he was assassinated before he could make any major changes.

George H. W. Bush (143)

Winning the Presidency following Reagan's retirement, Bush Sr. is remembered for the First Gulf War and for breaking his famous "read my lips" promise of not raising taxes. He was a former CIA director and WW2 naval pilot.

Chester A. Arthur (143)

Arthur's main legacy was the Chinese Exclusion Act, which was the first act totally preventing an ethnicity from entering the country. He was, at the time, greatly respected but he did not retain that reputation in popular memory.

Theodore Roosevelt (143)

Roosevelt was known being a bit of a renegade as a president, and enjoyed taking long hunting trips even when in office. He also broke up large companies with his anti-trust laws and built the Panama Canal. Also, teddy bears are named after him!

Grover Cleveland (144)

Cleveland was educated in law in New York. As President, his term saw the "Panic of 1893," a major economic depression, which ended his tenure as leader. Despite this, he won three Presidential elections beforehand.

Andrew Jackson (144)

Jackson's enduring action as President was the 1830 "Indian Removal Act," which has been considered an act of ethnic cleansing of the native population. Nonetheless, he won two terms and at the time was considered a hero for the Battle of New Orleans.

Benjamin Harrison (145)

Harrison was a progressive president and fought for voting rights for African Americans, but ultimately failed. He was also known for his longstanding feud with Grover Cleveland, who he defeated in an election, then lost to him again.

Woodrow Wilson (145)

Wilson became President in 1913 and pursued a compromise platform between progressive policies and his more conservative party. He tried to keep the U.S. neutral in the First World War but eventually entered it in 1917.

Rutherford B. Hayes (146)

Hayes was a lawyer and a soldier during the Civil War. Despite not winning an election outright, he was brought into office by rival Democrats on the condition he remove Union troops from the south.

Franklin Pierce (147)

Pierce, despite being a northerner, thought the union would be ripped apart by abolitionism. Legislation like the "Fugitive Slave Act" has been criticized by a large number of historians, and Pierce is seen as exacerbating the causes of the Civil War.

Millard Fillmore (149)

When Zachary Taylor died 16 days into his term, Fillmore was his successor. Despite his unplanned ascension to the Presidency, he was fairly successful, passing the Compromise of 1850 that delayed the Civil War by 12 years.

Franklin D. Roosevelt (150)

Also known as FDR, Roosevelt is widely considered one of the best presidents in U.S. history. He both oversaw the country's recovery from the Great Depression and lead it through to victory in World War Two.

John Adams (154)

The second President of the United States, John Adams was a very successful Boston lawyer prior to the American Revolution. He was widely known to be an eloquent man and his impact on U.S. history and law is extensive.

Barrack Obama (154)

Before becoming the first African American President, Obama was an Illinois lawyer. Widely regarded to be an intelligent man, his rule as President has, since leaving office, been fiercely debated for coming short of his election promises.

James Madison (155)

Madison was the fourth President of the U.S. and a Founding Father. He fought the War of 1812 against the British which was inconclusive and resulted in the White House being burned down by the British.

Jimmy Carter (156)

Though many consider Carter to be a intelligent and decent person, his Presidential tenure was unpopular. Events like the Iranian hostage crisis and continuing economic stagflation resulted in his defeat to Ronald Reagan in 1980.

Bill Clinton (159)

Clinton was President for most of the 1990s, had exceptionally good luck with the economy, and was extremely popular. Despite being impeached by Congress, he was not forced to leave office, and left when his term ended, with high approval ratings.

John F. Kennedy (159)

JFK was President during the Cuban Missile Crisis, the early space race, and entry into the Vietnam War. He is best known for his assassination on camera in 1963 by Lee Harvey Oswald — which is the subject of conspiracy theories to this day.

Thomas Jefferson (160)

Jefferson, the third President of the United States, was a polymath who was an expert in mathematics, law, and languages. His writings, even today, are considered the basis of American political ideology.

John Quincy Adams (175)

Not to be confused with his father, John Adams, John Quincy Adams was an excellent diplomat for the United States, a prolific writer, and important secretary of state. However, his reign as president was underwhelming.