It was supposed to be a watershed election, like those of 1932, 1968 and 1980, that would set America's course for a generation or more. Two years later, however, Barack Obama's sweeping victory in 2008 looks like one more blip on a political TV screen permanently obscured with static.
Given the closeness of some contests, the precise dimensions of the Democrat defeat in yesterday's midterm elections may not be known even by this evening. But unless every poll is utterly wrong, a massive defeat it will be. The House will surely have been lost – perhaps in the greatest swing of seats in half a century.
Even if Republicans fail to capture the Senate, one of the party's most respected strategists talks of the "largest ideological shift in the shortest period of time in my lifetime". But is it? And if so, what has happened in just 24 months to produce this transformation?
In fact, some of the social and demographic underpinnings of that imagined new era of Democratic dominance are still in place. In a time of economic crisis, people are looking to the government more for help, a mindset that ought naturally to benefit Democrats.
Hispanic voters – the fastest growing ethnic component of the electorate – have traditionally leant to the Democrats, and still do, not least because of entrenched Republican hostility to immigration reform. Thus new opportunities still exist for Democrats in the West and South-west, making up for the Republican takeover of the South that shifted the balance of power after the civil rights revolution of the 1960s.
But, far from being a springboard, the combined Democratic victories of 2006 and 2008 probably took the party to a high-water mark in Congress from which some decline was inevitable.
Since then George W Bush, that lightning rod of national discontent, has vanished from the scene. The Democrats' decline has also been speeded by the performance of Mr Obama, who has simultaneously managed to disappoint much of the liberal base while alienating the centrist independents whose support carried him to power.
A President supposed to be a master communicator has proved a surprisingly poor one from the Oval Office. Liberals believe he has been too timid in his reforms, while independents feel he has been, if anything, too liberal.
But something else is at work too: a volatility not seen in US politics since the 1940s. The last two Republican midterm surges, in 1966 and 1994, followed long periods of Democratic dominance on Capitol Hill. This time, it would seem, Democrats have been turfed out after just four years in charge. If Mr Obama were on the ballot against a generic Republican, he too would probably have been given his marching orders.
The biggest reason for this volatility is the economy. Travel anywhere in the country, and you find anger, confusion and fear among voters – a sense that the US may have entered a period of long-term decline for which neither party has the answer.
Americans are impatient too. Not only do they want answers – they want them to be fast and visible. Yes, Republican laissez-faire policies may have got the country into a mess. But Mr Obama has had two years to get the country out, and all people see is anaemic growth, high unemployment and record deficits. The Tea Party is a measure of this frustration. Whether the movement now takes root, or is defanged and absorbed into the Republican Party, is the great question of US politics.