Perhaps slanted towards the last half of the 20th century and the beginning of the 21st, weighted by the preponderance of video and audio coverage from what used to be considered routine campaign speeches, the selection of the best (or worst) political gaffes absolutely has to include the following.
1988 - Democratic Governor and presidential nominee, Mike Dukakis decided to take a photo opportunity at the US Army Tank Plant to show he could be viewed as a man who could command the military, despite no real experience there. The image of his head popping up out of the M1A1 Abrams tank and driving around the parking lot in his suit, led to his doom. He looked about as comfortable as Kermit the Frog holding a Claymore mine.
2004 - Howard Dean. A solid leader in the democratic presidential primaries, Dean was hitting the road hard and making stops in as many cities as he could. While getting the crowd fired up and excited after a stump speech in Iowa, his voice raised to the volume of a scream while pumping his fists and targeting the states where he needed to get the word out about his campaign. The end of the speech was punctuated with "YEAH", which was overplayed to the point where he sounded like a madman. Stick Howard with a fork. He's done.
2000-2002 George W. Bush quotes. "Rarely is the question asked: Is our children learning?"| "They misunderestimated me" | "Fool me once, shame on, shame on you. Fool me -- you can't get fooled again." | "This foreign policy stuff is a little frustrating." | "We need an energy bill that encourages consumption." Not sure we need to say anymore here.
Number 2. (Almost good enough to be Number 1)
2010 Newt Gingrich. After being questioned by Bob Schieffer in a recent interview, which included a request to explain the $500,000 line of credit at Tiffany's jewelry store, and an outstanding bill of somewhere between $250,000 and $500,000, Gingrich took exception to being asked about his private financial matters. Failing to make the connection to his political pitches for austerity measures in government and the horrors of the national deficit, Gingrich refused to elaborate on what was purchased on credit or for who. The following day, Gingrich made sure the press knew that he paid off the bill (which is a neat trick to be able to write a check that large), and reminded the press that "I am not a Washington figure". Perhaps that was a self fulfilling prophecy.
1998 Bill Clinton. What is your definition of the word "is"? Following a series of hounding interviews over the disclosure of a little blue dress incident with staffer Monica Lewinsky, Clinton was called into Impeachment hearings by the House of Representatives where under charges of perjury and obstruction of justice, he launched the famous quote, "It depends on what your definition of is, is". Yup. Good enough for me. This led to another statement where Clinton declared, "I did not have sexual relations with that woman". This was the new definition standard for all politicians that followed Clinton, because the implied meaning of sexual relations means penetration. A little tongue bath however, is apparently not sex. Got that? All clear now? Remember those clear distinctions while out on your next trip to Vegas.