If there was a sense of déjà vu among fans of Barack Obama crammed inside a university athletic arena in Hackensack, New Jersey, the other evening, it was entirely deliberate. They only had to close their eyes and listen to the deafening chants of "Yes We Can" to imagine they had been transported back to the heady days of a year ago when their candidate was on the verge of seizing the White House and making history.

Even with open eyes they could have felt some of that old frisson. Event organisers wandered the hall wearing shirts proclaiming 'Yes We Can 2.0', as if they were selling the latest Windows update, and a giant banner gave top billing to Obama. The name beneath his, Corzine, might almost have been an afterthought.

This was not a re-election rally for Obama – not yet, please – but for Jon Corzine, the former boss of Goldman Sachs and now governor of New Jersey. He invited the president to speak because, when Jersey voters go to the polls on Tuesday – New Jersey and Virginia are the only states where governorships are in play this year – it is not at all clear they won't ditch him in favour of his Republican opponent, Chris Christie.

The latest polls say it's too close to call. That's better than in the summer when Christie had a double-digit lead. But in the final stretch, Corzine needs to remind Democrats of 12 months ago when they overwhelmingly chose Obama over John McCain.

"One more time," the disco beat booms before the two men arrive on stage in front of about 3,000 supporters. "One more time. We're going to celebrate. Oh yeah. Alright."

Steady decline in ratings

Once at the microphone, Corzine promises to be brief. "I know who you came to see," he says. Obama does what is required of him with his usual eloquence, speaking for 30 minutes. He looks happy to be campaigning again, reliev­ed of Oval Office responsibilities for an afternoon, his stump oratory uncaged. But selflessness and politics do not go together. He is in New Jersey because what happens here next week will matter to him. The outcome of these two gubernatorial races will be viewed by some as a first referendum on his presidency.

Obama's approval rating has been in steady decline, so it cheers no one in the White House that the outcome in Jersey is so uncertain. In Virginia it is worse: most polls suggest the Democratic candidate, Creigh Deeds, will be walloped by his Republican rival, Bob McDonnell.

If Republicans seize the governors' mansions in both states, the embarrassment will be acute. That's what happened in New Jersey and Virginia in 1993 before Republicans seized control of congress the following year, dealing a crippling blow to the new Democratic president of the time, Bill Clinton.

But even losing one of them next week will scratch the sheen of Obama, who seems, a year on from his election, to be hovering between competent and fumbling in the view of most Americans, notwithstanding the high esteem in which he is still held abroad and, of course, in the minds of the Nobel committee.

What is certain is that the expectations placed on Obama that warm night in Chicago's Grant Park last November have given way to a general unease. For sure, he has mostly avoided calamity. Not getting the Olympics for Chicago doesn't count. Nor is his administration in disarray or anything close to it. (Clinton had barely arrived in office before he was engulfed in mini-scandals.) But the Obama magic that should be protecting Democrats such as Corzine and Deeds seems to be leaking away.

'Not the change we wanted'

New Jersey naturally belongs in the Democratic column. Moreover, since 1947, only two Jersey governors have failed to win a second term. But Corzine is unpopular in the state, thwacked by raising property taxes and the effects of the recession.

Virginia had been a red state since 1964 but it turned blue for Obama, and Democrats hailed it as a signal that their party was breaking the Republican lock on the South. The plight of Deeds – 11 points down according to a recent Washington Post poll – is being interpreted as a sign of how far the pendulum is tracking back to the Republicans in that state, and probably elsewhere.

McDonnell, the Republican candidate, will be the first to blame the president if he wins.

"There are blocs of independent voters that are being driven over because they are very concerned about these federal policies," he said. "Those voters probably leaned toward Obama in the last cycle. But when voters see specifics, I think some voters said: 'This is not the change we thought we were getting'."

Back in Hackensack, Carrie Wilkins, a 44-year-old hairstylist, is exasperated by the bad press the president has been getting.

"He has a very tough job," she says, arriving for the Corzine event with her 14-year-old son, Troy. "I don't think he has had a chance to do anything yet. He is trying, but it was such a mess when he came in. I kind of feel bad for him, actually."

Indeed, the attacks on Obama have become fiercer. Wisely or not, the White House has called out Fox News, saying it has abandoned all pretence of objectivity in the daily ear-boxing it gives Obama. Saturday Night Live, which last year so brilliantly skewered Sarah Palin, is getting sharper in its weekly skits on Obama. Meanwhile, the media stars of the right, notably Rush Limbaugh and Glenn Beck, continue to grow their Obama-bashing brands.

A broader picture, and a much prettier one, is provided by the polls. According to the Real Clear Politics poll of polls, the president's approval rating is still hovering above 50%, but only just. Sometimes we forget, however, to measure Obama against his opponents. Little fuss was made over a poll by CNN last week that showed the Republican Party with just 36% approval – its lowest in a decade.

A more reliable observer may be Troy, the schoolboy. Asked if Obama was doing a good job, he paused and then, with a shrug, said, "I guess so", meaning he, like many Americans, is not sure yet.

A lot of things are in the pending tray in Washington – the economy, for instance. While the signs of recovery seem to multiply almost daily, so do the warnings that this will be a largely jobless one, at least for the time being.

Healthcare reform

Pending also is the grinding effort to pass healthcare reform. This has been much more of a struggle than the Obama team – many of whom came to Washington with scant experience of its ways – expected. While momentum towards a deal seems to be building, a wise person would not bet on its passing just yet.

Healthcare is one of several areas where Obama has displayed characteristics that his supporters call patience and others call dithering.

"Healthcare could be his hammer," argues Larry Sabato, professor of politics at the University of Virginia. "If he gets it, he will have proven that his style works. But, if it falls apart or he gets a tiny piece of it, then there will be criticism that he is ineffective and not tough enough."

The narrative of a president who is too pliable has been growing in volume since the summer. Nor is it coming only from the right. There are those on the left who are infuriated by Obama's pragmatism. They object, for instance, when he refuses to push aggressively for the so-called "public option" to compete with private insurers in a new healthcare system, or when he declines to meet with the Dalai Lama in Washington because his agenda with China is more important to him. They even don't like it when he brushes off being called a liar by a member of congress.

"Nobody is really worried about the revenge of Barack Obama, because he is not a vengeful man," said Douglas Brinkley, a history professor and political biographer. "That's what we love about him; he is so high-minded, and he tries to govern with consensus – all noble goals, but they don't get you very far in this knifing environment."

As Obama takes his time deciding whether to send more soldiers to Afghanistan, he has again come in for attack, not least from Dick Cheney, who brooded in the shadows while in power but prefers daylight in opposition. "What Cheney calls dithering, President Obama calls his solemn responsibility to the men and women in uniform and to the American public," White House spokesman Robert Gibbs shot back. "We've all seen what happens when somebody doesn't take that responsibility seriously."

When Obama has been tough, it has been in ways that infuriate conservatives. He fired the CEO of General Motors this year before bailing the firm out, and in recent weeks took extraordinary steps to force banks to scale back outrageous executive pay deals. Both actions were bold, but they also represented interference in the market, which the right abhors.

Obama knows he is still on probation. In Hackensack, he asked the crowd "to cast aside the cynics and the sceptics and prove to all Americans that leaders who do what's right and who do what's hard will be rewarded and not rejected". It was meant as an appeal to Jersey voters to show mercy to Corzine. But he might also have been asking for understanding for himself.

12% - The percentage drop in Obama's approval rating since he became president

65,000 - The number of US troops in Afghanistan. Obama is considering a request from his top general for another 40,000

280 - The number of US troops killed in Afghanistan since Obama's election victory

$787bn - The size of the Obama adminstration's fiscal stimulus programme

$2.5m - The amount Obama earned in royalties from the sale of his books last year

3 - The number of presidents, including Barack Obama, to win the Nobel Peace Prize while in office

24 - The number of rounds of golf played by President Obama this year