'Ten years ago we had Johnny Cash, Bob Hope and Steve Jobs," runs a sour joke that has been doing the rounds since Silicon Valley lost its most famous son. "Now there's no cash, no hope and no jobs." Perhaps not a contender for the Nobel Prize in side-splitters, but it catches America's dark mood – a year to the day before the country delivers its verdict on whether Barack Obama merits a second term in the White House.

Before every presidential election, there is talk that this one will be historic, a "watershed" to match the two that truly qualified for that title during the previous century: 1932, which ushered in Franklin Roosevelt and five decades of Democratic domination, and the Reagan landslide of 1980 that made official a conservative shift in national politics that continues to this day.

The year 2008 was supposed to be another new beginning – not just in terms of the colour of the victor's skin, but in the vista of change, youth and renewal that seemed to open up, despite the worst economic crisis since the Great Depression that swept FDR into the Oval Office. But things didn't quite work out that way.

Great hopes can breed great anti-climaxes, and so it has been with Obama. The shining promise has not been fulfilled, at least not yet: in part because of his own inexperience (he had served barely two years in the Senate when he announced his candidacy in 2007); in part because of the singular bloody-mindedness of his Republican opponents; but above all because of an economic crisis that has proved deeper and more intractable than almost anyone expected.

The numerical truth was laid out last week in the latest forecasts from the Federal Reserve, the country's central bank. Growth for the next three years is unlikely to exceed 2.5 per cent – respectable by Euro-sclerotic standards, but barely enough to keep pace with a growing workforce. Even assuming a double-dip recession is avoided, unemployment will still be close to 9 per cent when the election comes around, and by late 2014 will probably still exceed 7 per cent. And that improvement may well reflect an increase not in the overall number of jobs available, but in the number of Americans who have given up looking for work. Remember, too, that no president since Roosevelt has been re-elected when the unemployment rate was above 7.2 per cent.

But figures tell only a fraction of the story. They cannot express the pervasive sense of decline, the feeling that this crisis is not just a blip, but a permanent inflection of the graph of national well-being. As long as the economy was broadly on the up, the injustices and shortcomings of the system were masked.

Worrying signs – increasing budget deficits, growing personal debt and a stagnation in middle-class incomes – have been around for more than a decade. But the Great Recession has brought them into glaring view, and may inspire America's voters into a revolution of their own. Frustration and anger are today's dominant emotions. You can measure them in the ascent of the Tea Party movement on the right, and the Occupy Wall Street (OWS) movement on the left. Ideologically, the pair are at opposite ends of the spectrum – the former seeing government as the source of every ill, the latter demanding that government stamp out the iniquities of capitalism run amok.

Compared with the OWS, the Tea Party is a relatively organised political force that now drives the Republican Party. But in a way they are two sides of the same coin. Both are exasperated with the status quo. Both loathe a system where money rules, where politicians are in the pockets of their financial contributors, and chief executives pay themselves obscene bonuses even when they have run their companies into the ground.

Even more fundamentally, the Great Recession is giving the lie to bedrock assumptions of the American Dream. The right to make a fortune has always been part of that dream, but within certain parameters of fairness. Those parameters are now stretched to breaking point. Hardly a week goes by without new statistics showing how national wealth is ever more concentrated in the hands of a very few. The gulf between the very rich and the rest is now wider than at any time since the 1929 crash. Liberals blame the Bush tax cuts of 2001 and 2003; these, however, only reinforced an existing trend, whereby technological advances rewarded the owners of capital and the superskilled, while globalisation of the labour market wiped out millions of traditional middle-class jobs in the US itself.

Another vanishing assumption is that each generation will be better off than its predecessor. Today's young Americans may well live worse than their parents, in a world where full employment in the traditional sense could be gone for good. Education, too, was supposed to be a key to eternally growing prosperity. Now Americans are constantly bombarded with evidence that their school standards are slipping dangerously behind their main Asian and European competitors.

American universities, it is true, are the envy of the world – as proved by the foreign students who flock to them. But the average debt of US students has risen to more than $25,000 per head, a record, while total student borrowing now exceeds total credit-card debt. And this when the decent jobs that will allow graduates to repay their loans are dwindling. America was supposed to be the land of social mobility. In fact, studies now show that if you are born into a poor family, you have a better chance of becoming rich in Canada and several European countries than in the US.

Which, in a way, leads back to Steve Jobs. Indubitably he was a titan of modern business, who has been compared to Thomas Edison or Henry Ford. But the grief at his death spoke to something more – a sense that a certain America had died with him, the America where a couple of kids in a garage could change the world.

Such fears, of course, are wildly exaggerated. The US is still the most inventive place on earth, as testified by patents taken out, Nobel prizes won, and crazes that sweep the world – not to mention the relentless industrial espionage against the US conducted by China, Russia and others. But the sense is palpable that the 21st century will not belong to America, and that global economic supremacy is shifting across the Pacific.

A less painful but still tangible contributor to the sense of decline is the ebbing power of the US abroad. Last week's G20 summit in Cannes underlined the point. Once, Washington would have been seen as a potential rescuer of the eurozone. These days, in debt to the gills itself, the US is a virtual bystander. All eyes are on China, with its $3.2trn of foreign reserves.

In military terms of course, America remains unchallenged, the world's only superpower, alone capable of projecting massive force instantly anywhere on the globe. But Washington can no longer afford another Iraq or Afghanistan, wars that have cost over $1trn, all of it borrowed money, and with little to show for it.

America's sway is waning too even in regions where its influence was traditionally huge. The US cannot shape an Israeli/Palestinian peace process; it watched from afar as the Arab Spring unfolded; and, in the honest but infelicitous phrase of an Obama aide, "led from behind" in Nato's Libya campaign. That approach may have made eminent diplomatic and financial sense. But for proponents of US exceptionalism and the country's global calling, it was thin gruel indeed.

Nowhere, though, is the disillusion, and the sense that the old ways no longer work, greater than Americans' views of their political system. When times were good, the imperfections did not matter: the federal government was traditionally a remote entity, and the checks and balances contained in the constitution were designed to keep it that way. But when times are bad, people look to Washington for solutions. Today's dysfunction and paralysis raise questions whether the two-party system in its present form is workable at all.

Americans, by and large, are pragmatists and moderates. Yet they look to Washington and see only polarisation and endless feuding between two parties driven by their extremes. In the US system of divided government, politics can work only by compromise, and compromise flows from the middle ground. Yet in Washington, the centre has mostly been destroyed. For the majority of incumbent senators and congressmen, the main threat they face is not the opposing party at the election, but a more radical rival in their own party primary, where a minority of committed activists determine the outcome.

The result is a Democratic Party dominated by its liberal wing, and a Republican caucus that has grown ever more conservative. Each is dug deep into ideological trenches. Americans generally favour robust argument and divided government – but not this divided. Checks and balances are all very well, but when one legislative body (the Senate) requires a vote of 60 of its 100 members for the slightest contentious legislation even to come to a vote, things, they feel, have gone too far.

After last summer's debacle over an increase in the national debt ceiling, dissatisfaction turned into disgust. A recent CBS/New York Times poll showed an approval rating for Congress of just 6 per cent – to which the common reaction is, who on earth are the 6 per cent?

But nothing seems to change. Last Tuesday, the House of Representatives did manage to pass, by a majority of 396 votes to six, a resolution reaffirming "In God We Trust" as the official motto of the United States. But anything that matters rots. The Republicans' theological aversion to higher taxes, even for the superwealthy, last week blocked a bill that would have provided jobs for hundreds of thousands, improving the country's ageing infrastructure. Similar resistance also looks likely to prevent the bipartisan congressional "super-committee" set up under the debt-ceiling deal from agreeing a plan for $1.2trn of further cuts in the deficit over the next decade by the appointed deadline of Thanksgiving. The price of failure may be a further downgrade of US sovereign debt by the ratings agencies – and yet more scorn for politicians from ordinary citizens.

No wonder Americans cast around for new saviours. No wonder the emergence of protest movements on both left and right, and no wonder the popularity of unconventional politicians such as New Jersey's blunt-spoken Republican Governor, Chris Christie, or Elizabeth Warren, Harvard professor, Democratic contender for the Senate and scourge of Wall Street and the financial industry.

The rebellious mood also helps to explain the weird contest for the 2012 Republican presidential nomination: the refusal to embrace the eminently qualified Mitt Romney and the flirtation with a string of alternatives, including the erstwhile pizza magnate Herman Cain, whose appeal, it would seem, not even a sexual harassment scandal can diminish.

The election is still a year off, and its outcome utterly unpredictable. In normal times, an approval rating of barely 45 per cent and polls showing 75 per cent of Americans believe the country is "on the wrong track" would spell big trouble for Obama. But, as the old sports adage runs, you can't beat somebody with nobody.

One thing, however, is sure. In this dark American moment, the stage is set for a populist. It could be the incumbent president, lashing heartless Republicans for their pandering to the rich. It could be a Republican who convinces his countrymen that Obama is leading the country to ruin. Or could a third-party candidate somehow become the outlet for the general exasperation with the status quo?

Don't write off the notion entirely. After all, the eccentric Ross Perot launched his candidacy only six months before election day in 1992, and won almost 20 per cent of the vote – in an age when America's problems were a 10th of what they are today. One way or another, 2012 could yet be the "watershed" election that 2008 was not.

IoS Special report: The State of the Union

Race for The White House

Republicans

January

9 Iowa caucus

14 Nevada caucus

17 New Hampshire primary

21 South Carolina primary

31 Florida primary

February

7 Colorado and North Dakota caucuses; Georgia and Missouri primaries

21 Wisconsin primary

28 Arizona and Michigan primaries

March

6 Idaho caucus; Georgia, Massachusetts, Oklahoma, Tennessee, Texas, Virginia and Vermont primaries

10 Guam, Kansas, and Virgin Islands caucuses

13 Hawaii caucus; Alabama and Mississippi primaries

20 Illinois primary

24 Louisiana primary

April

3 Washington DC and Maryland primaries

24 Connecticut, Delaware, New York, Pennsylvania, and Rhode Island primaries

May

8 Indiana, North Carolina, West Virginia primaries

15 Nebraska and Oregon primaries

22 Arkansas, Idaho and Kentucky primaries

June

5 California, New Jersey, Montana, New Mexico and South Dakota primaries

12 Ohio primary

26 Utah primary

August

40th National Republican Convention in Florida

Democrats

September

3 National Convention, Charlotte, North Carolina

National

November

6 Election of the President of the United States

Republican front-runners

Mitt Romney Governor of Massachusetts 2003-7. Ran for president in 2008, and now one of the two front-runners. Wants to lower corporate income tax, repeal Obamacare, cut public spending. Reputation as flip-flopper. Pro-life. Mormon.

Herman Cain Ex-CEO of Godfathers pizza chain, and outsider who has leapt into lead. Revelations that he was once accused by two women of sexual harassment have not derailed campaign – so far. Opposes government intervention in the economy through stimulus and bailouts, proposed much-criticised 9-9-9 flat tax plan which has helped his rise.

Rick Perry Governor of Texas 2000-now. Supports minimal government – low taxes and low spending, and repeal of Obamacare. Does not believe in gay marriage. Strongly pro-life. Never lost an election.

Statistics

313 million people live in the US.

13 per cent are black.

15 per cent are Hispanic.

33 per cent of Americans are classified as obese.

Life expectancy is 50th in the world at 78.4 years. Monaco is top with 89.7.

4.7 per cent of US GDP is spent on defence – twice the rate of China.

Three billion pizzas are sold in the US every year.

By the end of 2009, the US had 2,292,133 adults in prison.

45 per cent of US households possess a gun; there are 300 million firearms owned by US civilians.

$10.5 trillion US government debt is more than five times what it was in 1979.