My very own list of worst US Presidents, in order:
1. Buchanan: Result-620,000 deaths in Civil War
Kicker1: Supported Dred Scott decision which asserted that a colored man has no rights that a white man, or the government need observe.
Kicker 2: To the extent possible, disarmed northerners who moved to Kansas, so they could be safely murdered by pro-slavery partisans.
Kicker 3: Secretary of War Floyd moved all US cannon and small arms to southern bases/arsenals where they could be stolen by rebel forces.
Kicker 4: Provided US Government weapons to rebellious militia companies formed in the District of Columbia, in an attempt to prevent Lincoln from being inaugurated.
Mitigating: When loyal soldiers (including Abner Doubleday) inspected rebellious militia with a loyalty oath for the members to sign, he did not interfere. Militia companies who refused to sign the oath had their government provided muskets seized, and reissued to loyal companies.
2. Franklin Delano Roosevelt: Result- 407,000 US Military Deaths in WWII. German military participation could have been stopped with minimal casualties by a single US Marine Regiment sent to enforce the demilitarization of the Rhineland in 1935. He didn't do it, and rather, supported continued violations of treaty in the forced Anchluss with Austria, and the betrayal and dismemberment of Czechoslovakia.
Kicker1: Vice President Wallace was a paid Communist Agent, as verified by reading the Soviet side of the Venona Files after the fall of the Soviet Union. His affiliation was known to the US government long before that through signal decrypts. Wallace's treason was ignored.
Kicker2: Put US back into depression with his massive tax increases and bad government programs.
Kicker3: New Deal programs paid southern land owners, but didn't pay a cent to their poor sharecroppers, black or white.
3. Woodrow Wilson: Result: 117,000 US Military deaths in WWI
Kicker1: Re-segregated Federal Government
Kicker2: Prohibition jumpstarted organized crime in cities, and the southern rural branch, the Ku Klux Klan.
Kicker3: Drafted to fill army, and destroyed State Militia units. First man drafted was, irony of irony, a black man named Leo Pinckey. Many blacks didn't wait for the draft, some 700,000 volunteered and most served with valor.
Mitigating: Blacks exposed to less oppressive atmosphere in France could look forward to a more free environment when they returned. Many black units won major awards from the French, though denied comparable recognition by the US. The Harlem Hellcats had, at one time, a rather good commander, one Douglas MacArthur.
Kicker4: Centralized Army bases were breeding grounds for Influenza, which killed 650,000 to 850,000 Americans. Nearly 25 mission people were killed by flu around the world in the first year.
4. Lyndon Baynes Johnson: 58,000 deaths in Vietnam
Kicker1: Destroyed Black Families with Great Society welfare rules that only paid aid if the Father was not at home.
Kicker 2: Energized the long tradition of Democratic corruption in buying, creating and suppressing votes from the South to everywhere else.
Mitigating: Signed Civil Rights Act, passed by Republicans, which ended Democratic Oppression of Blacks in southern States. He had realize this would make it very hard for Democrats to win fair elections.
5. Harry Truman: 36,000 deaths in Korean War
Mitigating1: Desegregated Army
Mitigating2: Said "Marines? Isn't that the Navy's police force, but with a propaganda arm that would embarass Joe Stalin." Apologized afterwards, the wuss.
6. Jimmy Carter: Worst living former president. Result: Sold out US ally and provided an oil rich territory from which Islamic fascist nutballs could launch terrorist attacks.
Kicker1: Gave free amnesty to Vietnam era traitors, draft dodgers, deserters, and servicemen with bad conduct discharges (See John Forbes Kerry, hey what about that SF Form 180?) .
Kicker 2: Misery Index (Sum of interest rate, inflation, and unemployment) reached a US record.
Mitigating: Preaching about Human Rights was instrumental to fall of Soviet Union, a logical precursor to Reagan's "Evil Empire".
7. Slick Willie Clinton: Result: Flipped by Islamic Terrorists, bombed Christians that opposed Islamic Terrorists, thus guaranteeing additional terrorism since it worked so well.
Kicker1: fired 93 US attorneys General to hid his firing of the Attorney investigating him for fraud in Arkansas. Firing an attorney to influence an investigation is a felony.
Kicker2: Hid Iraqi involvement in first World Trade Center bombing, and hid fact that cyanide was laced inside the explosive in an attempt by the terrorists to release poison gas into the ventilation system. It was only good fortune, and terrorist incompetence, that the explosive burned hot enough to consume most of the poison.
Mitigating: Familiarized an entire generation of young women with the concept of Oral Sex.
Ok, I don't think that last is necessarily a good thing.