Having campaigned in poetry, Barack Obama doubtless expected to govern in prose. But it is arithmetic that threatens to cramp his ambitions. Last week, the Congressional Budget Office (CBO) released its long-term budget outlook. If current policies are continued, federal debt held by the public will rise from 41 per cent of GDP at the end of 2008 to 87 per cent by 2020, and (theoretically) to a staggering 716 per cent by 2080.

Meanwhile, Mr Obama is trying to save the planet and reshape America’s health-care system. The first task will be fantastically expensive. The second does not have to be, but probably will be. A president who refused to put off unpleasant decisions, as Mr Obama promised during his inauguration, would be honest about all this. He would tell Americans that stopping global warming means higher energy prices, and that arresting health-care inflation means cutting back on medical procedures that people want but don’t need.

Instead of straight talk, however, Mr Obama has mostly been offering happy talk. When the House of Representatives narrowly passed a climate-change bill on June 26th, he rejoiced that it would create millions of new green jobs and reduce America’s “dangerous dependence on foreign oil”. Almost as an afterthought, he mentioned that it might do something for the planet. As usual, he gave the impression that planet-cooling will require no sacrifice from voters.

This is drivel. The shift to a lower-carbon economy will destroy jobs as well as create them, and hit growth. Greens wish Mr Obama would use his immense popularity and rhetorical skills to persuade Americans that such costs are outweighed by the benefits of helping to avert planetary catastrophe. But rather than shaping public opinion, he is running scared of it. And so, even more, is Congress.

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