I agree that political discussions have no place on this forum. Hell, we can't talk about sailing without getting mad at each other, let alone politics.
But, since you've opened the nominations for worst president, I have to second the nomination of Lyndon Johnson. He campaigned against Goldwater, claiming that if Goldwater was elected, he would get us into a war within 6 months. (If Eisenhower had already gotten us into the Vietnam War, as some like to believe, nobody at the time knew about it, because Johnson's campaign strategy was to play on the public's fear that Goldwater would get us into a war.) Sure enough, 6 months later, Johnson commenced our first major involvement in the Vietnam war. Before the end of his term, the allies had well over a million troops in Vietnam, many of whom were US draftees. Johnson was so frustrated by the continued escalation of the war, and his inability to stop it, that he appeared on national television one night and announced that, if nominated by his party, he would not run for reelection, and if elected, he would not serve another term as President. He made a complete mess of that war, he knew it, and he quit at the end of his first full term, leaving it to Richard Nixon to figure out a way to get us out of it. That is the definition of failure.
I know it's difficult for some to imagine, but history will ultimately be much kinder to Richard Nixon, who ended the bloodshed in Vietnam and who opened up relations with Communist China, which, as we all can now see, after the passage of 35 years of history, is rapidly becoming the next great economic powerhouse of the world. Despite his impeachment, those will be seen as Nixon's towering achievements.
For those who are so ungracious in their opinions of President Bush, he too will fare well in the long-term vision of history. The opposition will be seen as a pack of snarling dogs, acting out of a blind rage, and he'll be seen as a man who led the nation where it needed to go, even though it didn't want to go there, and that is the definition of greatness.