US politics is one of America's many gifts to the world - as free theatre, it's hard to beat. It can be pretty funny unassisted, and the late-night TV comedians add an extra layer of levity. The smooth, middle-aged movie star looks of the Republican candidate for the presidency have been a source of fun:
''Mitt Romney looks like the guy in the photo who comes with the frame,'' David Letterman said. ''He looks like the guy at the Cadillac dealership who comes out to close the sale.''
The misinformation campaign claiming Barack Obama is an illegitimate president because he was not American-born has been an endless source of gags:
''The Republicans are so happy about the killing of bin Laden, they've granted President Obama full citizenship.''
But the jibes can be telling because they sometimes go to the heart of the big problems stalking America: ''Mitt Romney is claiming he's going to create 12 million jobs in his first term. But he hasn't said yet if he'll create them in China or India,'' Conan O'Brien said.
And this one from Jay Leno: ''President Obama released his tax returns. It turns out he made $US900,000 less in 2011 than he did in 2010. You know what that means? Even Obama is doing worse under President Obama.''
Because, beneath the bunting and beyond the showbiz and sideshows, the elections will affect the US and the world in important ways, and that means it will end up affecting Australia too.
The most urgent problem that will loom after election day on November 6 will be the so-called ''fiscal cliff.'' If the US goes over this cliff, it will fall into recession, and take much of the world economy with it.
The ''fiscal cliff'' is the colloquial name for the event that will occur automatically at the end of the year if the US political system can't agree on a budget that will start to reduce the federal deficit.
It was deliberately set up by the Congress as a kind of ticking time bomb. Congress couldn't trust itself to solve the problem in a normal way, so it pre-programmed a deadline for itself with drastic consequences if it wasn't met.
It's structured as a drastic $US1 trillion set of cuts to government spending, including a half-a-trillion-dollar cut to the defence budget. And it includes an onerous increase in taxes - it's also been nicknamed ''taxmageddon''. The average tax burden on the American household would rise by $US3500 next year, according to the independent Tax Policy Centre.
The cliff's more formal name is sequestration. It's supposed to be so scary that no one in his or her right mind would allow it to happen.
Unfortunately, it needs to be agreed, not between people in their right minds, but by the politicians in the Congress, together with the White House.
The chairman of the US Federal Reserve, Ben Bernanke, has called it a ''massive fiscal cliff'' that ''would probably knock the recovery back into a recession and cost a lot of jobs, and would greatly delay the recovery that we're hoping to facilitate''.
The US is the only major economy with decent growth momentum at the moment. If it goes over the fiscal cliff, there will be none.
Republican and Democrat congressional leaders are intransigent on a budget deal. But the Republicans are especially doctrinaire. The Democrats demand a combination of spending cuts together with tax increases.
The Republicans, though, will agree only to spending cuts. In last week's presidential debate, we saw Mitt Romney repeat this unrealistic mantra of no tax increases whatsoever.
Why is this unrealistic? Because US federal revenues since the global recession have fallen to about 15 per cent of gross domestic product. This is the lowest since the Korean War broke out in 1950. The average in recent decades is 19 per cent.
With spending at 24 per cent of GDP, there is no way to close the deficit by spending cuts alone. Both spending cuts and tax increases are inevitable in any realistic scenario. If Romney is elected president, the Republicans will claim vindication. The chances of Republican compromise fall sharply. The chances of a new US and global recession increase sharply.
The next big pressing problem that will occupy Australia's attention is the US view of China. The US election comes just two days before the Chinese Communist Party transfers power to a new president, Xi Jinping.
What happens in the relationship between these two powers in the next few years ''will very much determine the future peace, stability and prosperity of the Asian hemisphere through until mid-century,'' as Kevin Rudd put it in a speech on Friday.
''For it is during Xi Jinping's second term that China could well surpass the US as the world's largest economy. And this will be the first time since George III that a non-Western democracy will become the world's largest economy.''
Rudd proposes a set of arrangements to allow the US and China to better manage their relationship, the world's biggest trading partnership. But who will the US elect to manage it, and does it make a difference?
As the director of the Lowy Institute, Michael Fullilove, argues in his paper published today, the differences are probably smaller than they seem. Obama's original approach of conciliation towards Beijing has toughened.
China's leaders ''were not impressed by Obama's life story, his uplifting speeches or his Portuguese water dog. In response, Obama's China policy hardened.''
Among other measures, he proceeded with arms sales to Taiwan, met the Dalai Lama, and declared the ''Asia pivot'' to strengthen the US military presence in the Asia-Pacific.
''The stiffening of US policy gave pause to Beijing and both sides seemed to reach a modus vivendi.''
Romney has talked of toughening yet further, promising new sanctions on China over its currency and trade policies from his first day in the White House.
But Obama, when he was campaigning at the last election, promised to do the same. Fullilove concludes Romney would be tested, but probably end up running very similar approaches to those of Obama. The main difference here, it seems, is the risk of the unknown, a new and untried leadership.
The theatre of the election can be very funny; the aftermath will be no laughing matter.
Peter Hartcher is the international editor.