This $800billion stimulus package may hang over President Obama as much as the Iraq war did over President Bush. It costs about the same, for a start (taking just the direct military costs of the war).

Already, Republicans are reborn from their post-election gloom, accusing him of saddling the US with huge deficits for years to come, and of filling the Bill with “pork” - favours for special interests. Protesters greeted him on his race around the country with pink, pig-shaped signs. They have a cause around which to rally, their leaders boast (although quietly, for fear of being thought to scupper the salvation of the US, and the world).

The attacks are overstated, dripping with scorn and ideological certainty although the package defies political characterisation. Indeed, Obama's best protection is that the essential nature of the sprawling, cluttered Bill is hard to summarise. So it will not be easy to pronounce either failure or success. But even some of his own supporters sound worried that his first big move, the most important he may make, is so messy.

Republican commentators have had a field day picking out items of “pork-barrel politics”. As Charles Krauthammer, of The Washington Post, put it: “It turns out the ‘fierce urgency of now' includes $150million for livestock insurance.” These gibes aren't their strongest points, for all the easy comedy the examples produce. But critics are right that too many items are crafted to suit local interests, which would normally be paid for by states, counties or even towns.

In Obama's defence, the big building blocks of the package represent his campaign promises on renewable energy, healthcare and education. But his weak spot is in arguing that spending on these will create many jobs. Martin Feldstein, an economist who was an adviser to Ronald Reagan and who is now president emeritus of the non-partisan National Bureau of Economic Research, has written that the Bill in the House of Representatives was “an $800billion mistake”. He called for a stimulus before the November election but says that this one boosts spending or jobs by too little.

Democrats can rebut political attacks by pointing out that the Bush years - and the Iraq war - turned a healthy budget surplus into huge deficits, and left the US ill-equipped to deal with the downturn when it came. Politics aside, they are on shakier ground defending the merits of the patchwork that they, and their starry new President, have stitched together in such a hurry.

It may work. There are still good reasons why the US economy might recover faster than Britain's, for example. But at this point, before the money has been spent, there is good reason to worry.

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