6) Herbert Hoover
Hoover worsened the Great Depression by hiking taxes and starting a trade war with other nations. His mid-road approach between government aid and individualism resulted in no major reforms needed to recover the economy. Also, he ordered an army to attack veterans who were demanding for their pension.

5) Lyndon Johnson
His failure of escalating Vietnam and refusing to withdraw. He poorly commanded the war, micromanaging it himself. His hyperinflationary policies to fund the war resulted in the bad economy in the late 1970's.

4) Andrew Johnson
He promised no mercy to confederacy while vice-president, but when he succeeded Lincoln, he was very lenient to high-ranking confederates. After the civil war, he vetoed every single bill which would give African Americans equal rights and supported state governments which condoned lynching and discrimination for the next 100 years.

3) Franklin Pierce
He was a slaveowner who later supported the confederacy during the civil war. He added several slave states to union which would later side with the confederacy.

2) Woodrow Wilson
An idealist who was completely out of touch with reality who reated one of the worst bureaucracies in all of world history, the Federal Reserve. Provoked an unnecessary entry into World War One which resulted in many negative consequences for our country.

1) James Buchanan
He called slavery an issue of little practical important, just shortly before the civil war erupted. As the southern slave states were seceding, he literally did nothing and anxiously waited for his term to end to hand over the greatest issue of American history to his successor.

Runner-Ups: Warren Harding, Ulysses Grant

I'm not sure what part of "chronology" you don't understand, but you might want to check the dates on the history of Islamic terrorism before attempting to blame it on the Islamic Revolution in Iran in 1979. That was probably the high point prior to 9-11. But it's not like that was the starting point.

And the PLO is an organization that was scattered throughout the middle east. Iran became a home base for all anti-american and anti-israel terrorist organizations. Prior to this, the amount of radical islamist attacks were not so numerous.

Once the Ayatollah took over Iran, it became the most feared terrorist state in the world aside from Saddam's Iraq.

So in that sense Carter failed to stop a group of radicals from taking over a western ally. He failed on this, not to mention his domestic policies.

If you are going to blame someone for their failures as a President, at least give them the credit for something they actually failed on.

Iran arms and finances any muslim terrorist organization againt Israel. Carter could have deterred this, but instead he let his good boy ideas get the best of him.

Pierce did nothing to stop the southern states from seceding. By doing this he essentially let the civil war start.

Carter withdrew support for the Shah of Iran. This caused the Shah to be overthrown by radical islamists who are currently fighting us. Carter is responsible for the start of terrorism in the middle-east.

Next in line is that infamous idiotic Texan Lyndon Banes Johnson for being directly responsible for the deaths of over 50,000 American fighting men.

After him comes FDR for his contribution to our involvement in WW2 and the idea of that most impotent of organizations called The United Nations.

At the bottom of the barrel, strictly because he ushered into American Politics the bane of us all to this day, namely the Progressive Movement, which in fact is nothing but socialism in disguise is none other than Woodrow Wilson. FYI – He was duped into signing the Federal Reserve Act by his Progressive cronies and which he later made the statement that was the only regret that he carried from his term as President.

There you have it . . .

My not-so-humble opinion.