Once an apparently inexhaustible source of humour, American politics is in danger of becoming satire-proof. How do you send up something that's already a self-parody?
With the gloss, razzmatazz and focus on personal narratives, it has always been hard to tell where politics ends and showbiz begins. The sight of Clint Eastwood talking to a chair at the Republican Party convention suggests the distinction is now largely academic.
There are few clearer demonstrations of the power of celebrity than the spectacle of members of a party dominated by religious fundamentalist social conservatives going ape over a speaker who is pro-choice, pro-gay marriage and has fathered seven children by five different women, only two of whom managed to get him to the altar.
Eastwood is entitled to be partisan and politically active, but this performance would have shocked many fans. Not because he's right wing - he flagged that many years ago - but because of the yawning chasm between his screen persona and the real person.
Before our eyes, the Man with No Name was revealed as the Man with No Off Button.
The actor who plays taciturn loners came across as the sort of windy old geezer who insists on making speeches at wedding receptions even though he's not entirely sure who's marrying whom.
Celebrity endorsements are based on the premise that we should take notice of what famous people think, even when they venture outside their areas of accomplishment. Americans should bear in mind what Clint had to say on this subject in the Dirty Harry movie The Dead Pool: "Opinions are like ass****; everybody's got one."
Then there's the question of truth. We expect politicians to dissemble, distort and generally be economical with the actualité, as the late English writer and politician Alan Clark (another prolific womaniser) put it in order to get around the parliamentary convention that you can't call another MP a liar.
And politics American-style has never been a sensible pursuit for the fastidious or thin-skinned. Embroiled in a tight election campaign, long-serving Democrat congressman and future president Lyndon Johnson instructed an aide to spread the word that his opponent had an unnatural and illegal interest in farmyard animals.
When the aide protested that it wasn't true, Johnson replied: "I know, but let's make the son of a bitch deny it."
Even so you have to be pretty cynical to expect a politician making a nationally televised address designed to demonstrate his fitness for high office to tell one barefaced porky after another, as Republican vice-presidential candidate Paul Ryan did.
Ryan's speech was so brazenly and demonstrably deceitful that it came as no surprise to learn that in a media interview he'd claimed to have run a marathon in under three hours when it really took him over four. This is like a golfer claiming to have broken par when he actually carded three figures - ie, not an easy mistake to make. In fact, not a mistake at all, just calculated, self-aggrandising dishonesty.
You'd have thought both Eastwood and Ryan would have been more conscious of protecting their brands. Ryan, after all, has been portrayed as a policy heavyweight, a master of detail dedicated to defusing the federal government's budgetary time bomb: principled, intellectually rigorous and, above all, numerate.
Then there was presidential candidate Mitt Romney's more in sorrow than in anger claim that, for America's sake, he had wanted Barack Obama to succeed and was genuinely disappointed that he hadn't. While no doubt intended to strike a chord with independents who fell for Obama in 2008 but may now be experiencing voter remorse, it was also beyond disingenuous given that US politics over the past four years has been defined by the Republicans' relentless campaign to obstruct, de-legitimise and destroy Obama's presidency.
This campaign was launched at a dinner attended by 15 leading Republican congressmen, including Ryan, on the day of Obama's inauguration: January 20, 2009.
And in October 2010 Republican Senate minority leader Mitch McConnell made it crystal clear that his party's overriding concern wasn't America's indebtedness, its foreign entanglements or the sickly economy: "Our primary goal in Congress is to make Barack Obama a one-term president."
What would be the response to a scriptwriter who pitched the following premise for a satiric study of American politics: an idealistic young Afro-American running against a fat cat from central casting, a fabulously rich white corporate raider who shifts his money around the world to avoid paying tax and is backed by a shadowy, unaccountable cabal of ruthlessly self-interested billionaires.
Probably something like: "Too contrived, too crude and, if you'll pardon the expression, too black and white. Back to the drawing board."