A “gaffe” is an unintentional comment that causes a politician embarrassment.
The term often refers to a politician inadvertently saying something publicly that they privately believe is true, but would ordinarily not say because it is politically damaging.
Michael Kinsley: “It used to be, there was truth and there was falsehood. Now there is spin and there are gaffes. Spin is often thought to be synonymous with falsehood or lying, but more accurately it is indifference to the truth. A politician engaged in spin is saying what he or she wishes were true, and sometimes, by coincidence, it is. Meanwhile, a gaffe, it has been said, is when a politician tells the truth — or more precisely, when he or she accidentally reveals something truthful about what is going on in his or her head. A gaffe is what happens when the spin breaks down.”
New York Observer: “In a world of YouTube, where everyone’s a video camera, publicized moments of misstatement and accusation presumably will only increase. But why do some public people in these cross hairs self-immolate while others endure and prevail? Maybe it’s because they ignore a few simple rules.”