This is usually a very subjective issue, and the answers are always very contradictory and confusing. However, there are some more objective ways to judge U.S. presidents, based on their values as leaders, the way they handled a crisis, internal and foreign policy, and many other actions. The American Political Science Association recently created a system of ranking, based on objective merits and 162 members discussed, evaluated, and judged the presidents in comparison to facts. Check out the results in the list below.
Did you know that in most polls and discussions by historians, James Buchanan is the worst U.S. President in history? His policy towards people of African origins and slavery influenced the Dred Scott decision, announced by the Supreme Court in 1857, which states that people of African origins can't be American citizens, no matter if they were slaves or not. The decision was a major factor that led to the Civil War.
Warren G. Harding
He was president for only two years, but in that short period, he managed to get involved in various incidents and scandals. He appointed his closest friends aka the Ohio Gang to the highest positions in the government, and they took advantage of it in the 1920s. He once said "I have no trouble with my enemies, but my d*** friends, my God-d***** friends… they’re the ones that keep me walking the floor at nights!"
Johnson was the president after Abraham Lincoln in 1865. He was against the Fourteenth Amendment, which allowed former slaves to be citizens of the U.S. A letter he sent to the Missouri governor included: "This is a country for white men, and by God, as long as I am President, it shall be a government for white men."
The worst decision during his time as president was certainly the Kansas-Nebraska Act in 1854 which referred to the question of slavery in the West. More precisely, the question of expanding it further. His inabilities to be a leader and to make his own decisions are also some of the reasons why he was one of the only presidents whose own party did not nominate him for a second term.