Jimmy Carter has done more economic damage to the U.S. than the 9/11 attack.
He may be the root cause of 9/11.
That is the absolute truth although most people aren't aware of it. He did grievous damage to the maritime industry. I know, I have lived (and suffered) through it.
One could make a case that had we not had a Jimmy Carter we may never have had a 9/11. His pasifism during this presidency, refusal to help the Shah of Iran, etc., helped set up events leading to that fateful day.