Can the USA save the world? The uncertainty that Americans face over fiscal policy will come into much sharper focus in the second half of the year. Economists at Bank of America, for example, believe consumers and companies will put a break on spending and investment until there is greater clarity on the tax increases and spending cuts that will be employed to reduce the country's more than $15 trillion of debt. It is the latest headwind for a recovery that was blighted in 2011 by threats from overseas, starting in the first quarter with the oil price spike and ending with the escalation of Europe's debt crisis. Although fiscal policy is the new cloud in view, the first three months of the year delivered plenty of bright spots for an economy that many still hope can meaningfully strengthen this year. The brightest of all has come from the country's jobs market, where 635,000 Americans found work in January, February and March. That sustained a trend that has seen the unemployment rate tumble from 9.1pc in August to 8.2pc last month. Bernanke, who has consistently put the accent on the hurdles still facing the economy, acknowledged that "a substantial portion of the decline in the unemployment rate does reflect genuine improvement in labour market conditions." As importantly, there is evidence that the greater number of jobs now available is giving US consumers more confidence to spend. Consumer credit jumped by $17.8bn to $2.51 trillion in January and, after counting increases in November and December, added up to the biggest three-month gain in a decade. Perhaps the clearest sign that some borrowing is becoming easier for consumers can be found in the US car industry. Banks are charging American drivers the lowest interest rates since 2009, according to Experian Automotive, as fewer buyers fall behind on payments. "It's good that thus far this year consumer spending and, for the most part, consumer confidence has held up well," said Michelle Girard, an economist at the Royal Bank of Scotland. The bank is one of several that has been forced to raise its forecast for how quickly the economy expanded in the first three months of the year. President Barack Obama has a grand ambition to increase US exports and wean the economy off its reliance on consumer spending. Not even his staunchest supporters would say that it is "job done." But evidence is emerging that the world's economic engine room is spluttering back into life. And it is the American consumer that everyone is watching like a hawk. Spending by US households accounted for 70pc of America's GDP in 2011, according to the Commerce Department. That is why the economic health of Mr and Mrs America remains critical to the recovery's prospects this year. Encouragingly, there are signs that Americans have worked off some of the debt binge that helped plunge the economy into its deepest downturn since the Great Depression. US households have reduced their ratio of debt to disposable income by 15 percentage points since the end of 2008, according to a recent report by McKinsey. The management consultancy forecasts that by the middle of next year households should be back to the ratio experienced before the last housing-led bubble. Few would argue though that it is time to crack open the Budweiser. While economists have spent the past week ratcheting up growth forecasts for the last quarter, barely anyone has done so for the year as a whole. The consensus is that the US economy will expand between 2pc and 2.5pc, unchanged from the start of the year. There are a number of explanations for the relative pessimism, some within the economics profession itself. More than three years on from the collapse of Lehman Brothers, economists still debate whether the US economy's potential has been permanently reduced by the crisis. Throw in the fact that almost all forecasters were left embarrassingly wrong-footed by the economy's disappointing performance last year - it grew just 1.7pc - and it is not a surprise that few are racing to be cheerleaders for its prospects now. "After the first three months of the year people are a little more confident about the durability of the recovery," says Bob Diclemente, an economist at Citigroup. But just because it's durable, doesn't mean it's going to be strong. The reasons for this caution are not, of course, all inside the heads of economists. With less than nine months of the year left, the US recovery faces headwinds in the real world - starting with petrol prices. American drivers are paying about 20pc more to fill their tanks now than at the start of the year, and a gallon of fuel reached $3.90 at the end of last month. The increase has dominated political debate over the past two months, with Republicans seizing on it to attack President Obama for an energy policy they claim has not adequately shielded Americans from rising global demand for crude. "A sharp jump in the price of oil and gasoline can squash a recovery pretty quickly," said Zentner of Nomura. Nomura calculates that a $10 increase in the price of oil sustained over a year knocks 0.2 percentage points off US growth. The comfort so far is that consumer spending and confidence is proving resilient. That is partly because gasoline prices have not spiked as quickly as they did in the first quarter of last year and are still below the three-year high reached last May. However, the fear remains that an escalation in tensions over Iran's nuclear programme could easily see prices vault to levels that deepened America's recession in 2008. Besides releasing some of its Strategic Petroleum Reserve, there is little the US government could do to tame crude prices. This limited ability to influence events is how many in the US feel about the other central threat from outside the US - Europe's debt crisis. Bernanke, whose caution baffles and irks the more bullish in America, last month welcomed the easing in financial tensions that followed the European Central Bank's (ECB) decision in December to provide cheap, three-year loans to the Continent's banks. Although the eurozone was home to 13pc of US exports last year, the effect of the crisis on trade has always been a secondary worry next to the threat it poses to America's financial system. It is that threat that prompted the Fed to provide hundreds of billions of dollars to European banks at the end of November and, less than six months on, there remains real concern in Washington and on Wall Street that the crisis could again escalate. "Europe has bought some critical time [with the ECB's measures]," says Diclemente. We're struggling on this side of the pond thinking about the contagion issue. These financial linkages are not always easy to identify - they run pretty deep. American economists see a cluster of potential threats - a severe spike in the price of crude, further turmoil in Europe and a sharp slowing in the Chinese economy. From overseas, many see a different picture - an economy that has made meaningful progress over the past six months. Both are accurate. America's long-term challenges - increasing exports and developing an energy policy, to name just two - remain. But if the outside threats don't materialise, one economist describes 2012 as an "opportunity" to strengthen the recovery in the world's largest economy. And even Bernanke is perhaps growing a little more confident, as the Fed last week signalled a third round of quantitative easing will happen only if the recovery falters. Given the demanding fiscal challenge still facing the country, it cannot afford to.