Leading article: President Obama still offers change we can believe in

It is hard to find an American with a good word to say about Barack Obama at the moment. The President is denounced by his progressive supporters for being insufficiently liberal. He is attacked by the libertarian Tea Party movement for being a communist. He is slated by the leaders of corporate America for his supposedly "anti-business" policies. Everywhere, there seems to be anger and disillusion. The contrast with the mood of optimism and hope when Mr Obama was elected two years ago is remarkable. And the expectation is that these currents of national discontent will mean heavy losses for the Democrats in today's midterm congressional elections.

But if Americans believe responsibility for their national ills can all be laid at the door of their President, they are deluding themselves. There have indeed been mistakes from the Obama White House, mainly over the economy. Mr Obama's gravest error was to leave the US public with the impression, after the stimulus was enacted, that growth would rapidly return and that unemployment would fall. Two years after the financial crisis, the economy is still weak, unemployment still high and the President is duly taking the blame.

There have been policy disappointments too. The financial reform Bill was weak, ignoring the threat posed by America's too-big-to-fail banks. And the deal cobbled together at the Copenhagen summit on climate change was nothing more than an exercise in saving face. Yet the charge that Mr Obama's two years in office have been an unmitigated disaster is nonsense.

The stimulus package, though too small, was enough to neutralise the threat of a slump on the scale of the Great Depression. And Mr Obama managed to pass a healthcare reform Bill that will grant coverage to millions of presently uninsured Americans, a prize that has eluded previous Democratic presidents for decades.

The impossible political context must be recognised. In Congress, Mr Obama has faced a Republican Party incapable of legislative compromise, lurching to the populist right. He has faced the rank ingratitude of corporations and banks, who have lambasted the President for being insufficiently solicitous of their needs, even as his administration bailed them out with hundreds of billions of taxpayers' dollars. Abroad, Mr Obama had to deal with short-sighted European leaders dogmatically insistent on slashing their own deficits in the expectation that America would, as usual, pick up the slack in the global economy. In China, he faced a rising economic giant unwilling to sign up to serious action on reducing carbon emissions. Under these circumstances, it is a wonder that Mr Obama has achieved anything at all.

And it is to the President's credit that, despite all the popular anger, he has stuck to his central course and refused to pander to the basest instincts of the American electorate. It is that very steadfastness that makes it possible that Mr Obama will still lead the US successfully through this present period of economic turmoil. There are other grounds for guarded optimism. If the Republicans win control of Congress, they will no longer be able to merely say "No" to everything. Democratic defeat in these elections could, some suggest, open a productive new chapter in Mr Obama's presidency, just as it did for Bill Clinton in 1994.

The opinion polls suggest that US voters will today release a howl of rage and pain, and the Democrats – as the ruling party – will take the brunt of that anger. But the obituaries for the Obama presidency are premature. The audacity of hope remains.