I have long been fascinated by the self-evident public lie. Sometimes the product of desperation, sometimes arrogance, sometimes contempt, each example poses a set of equally unattractive interpretations. Does the liar really believe the obvious lie is true, in which case he or she is deranged? Does the liar think that enough people will believe something so demonstrably false, meaning that he or she holds a deplorable lack of respect for the intelligence of the public? Is the liar so fearful and cowardly that he or she cannot summon the integrity to admit what is obvious, even though doing otherwise looks ridiculous? Or, as is surprisingly often the case, does the liar have so little regard for the truth and such a deficit of shame for lying that he or she doesn’t care that the lie is obvious?

When elected officials and others holding high office resort to the obvious lie in a matter of any importance, it should disqualify them from continuing in office. An obvious lie obliterates public trust. For example, when Janet Napolitano had the gall to pronounce department’s anti-terror airplane security measures a success because, be sheer luck, passengers foiled the so-called “Underwear Bomber,” she forfeited any future trust in her honesty of competence. (She is still Secretary of Homeland Security, however.)

The excuse sometimes offered by obvious liars after the fact is an ethics “Catch 22.” They argue that an obvious lie is a harmless lie, because nobody could possibly believe it. (Over on “The Ethics Scoreboard,” a spectacular version of this argument launched the continuing feature of “The David Manning Liar of the Month,” after Sony tried to justify its use of a fictional movie critic, “David Manning,” to attach glowing—but fake— blurbs to lousy films, like the Rob Schneider comedy “The Animal.” When its deception came to light, Sony protested its practice was harmless because nobody believed critical praise in movie ads anyway.) The defense conveniently ignores the question of why anyone would offer a lie they didn’t expect anyone to believe. It is really a consequentialist scam: if I try an outrageous lie and it works, great; if it doesn’t, then it wasn’t a lie.

What do we make, then, of Sen. John McCain’s stunning claim in a recent Newsweek interview that “I never considered myself a maverick” ? This could stand as the epitome of a transparent lie. McCain’s entire presidential campaign, to a nauseating degree, was built on the premise that he is a maverick. His ads—approved by him, per commend of the F.E.C., said he was a maverick. He said so himself, in his stump speech, repeated all over the country. If he never considered himself a maverick, why did he keep saying he was one? After proudly calling himself a maverick for years, how could he possibly expect anyone to believe that he never considered himself one?

On Fox News Sunday, host Chris Wallace asked McCain to explain. The senator had one shot, and it was to say this: “You know, sometimes when you’re in a campaign mode [McCain is in a tough primary fight in Arizona against challenger J.D. Hayworth] and you’re giving interviews left and right, things come out wrong. Obviously I have referred to myself as a maverick. What I meant to say was that being a maverick by itself isn’t anything to be proud of. I’m a maverick in the sense that I fight for what I believe in, even if it means fighting alone. I meant to say that I never considered myself just a maverick.”

Instead, Sen. McCain ducked the question, not once, but twice. Thus all we can conclude is that McCain, at a time when he knows that his long record of bucking the conservative Republican agenda is putting him at risk of losing his job, is desperately trying to convince voters that an unavoidable fact doesn’t exist. In this he is emulating the greatest of all obvious lies, Jimmy Durante’s classic response in the Rodgers and Hart musical “Jumbo.” As he tries to sneak a huge elephant out of the circus, Durante was stopped by a sheriff who barked, “Where do you think you are going with that elephant?” Durante’s reply: “Elephant? What elephant?”

Durante’s obvious lie is a joke, but McCain’s is not. John McCain’s career has been built on his character,honesty, courage and integrity, and in denying his own elephant, the Senator denies all three. When a public figure whose greatest assets are supposed to be these begins trading in transparent lies, it is time for him to retire, no matter who the alternative is. The culture of deceit and manipulation in politics has eroded his values and ethical instincts.

We are always better off with a maverick than a transparent liar.