Why on earth does anyone want to be President? At the end of April, Barack Obama must have thought that his ducks were finally lined up in a row. He had pulled off the biggest overhaul of US healthcare in half a century, and was about to apply similar treatment to the wicked barons of Wall Street.

Yes, a rig explosion had just killed a dozen workers and caused a significant oil spill in the Gulf of Mexico, but there seemed no reason for outsized alarm. In the six months before November's mid-term elections, the White House could devote its energies to the issue that most pre-occupied ordinary Americans: jobs, or rather the lack of them. Some hope.

The Deepwater Horizon calamity now utterly dominates American politics. For the sake of the Gulf and its wildlife, of the states that border it and the people who live off it, we can only pray that BP succeeds in its latest attempt to cap the ruptured well. Even so however, the after-effects of the disaster will linger for months, probably years.

The same is true for Obama. For him as for the well, damage containment is now all. Yes, his handling of the disaster has not been perfect. Initially the White House – like almost everyone else – underestimated its size; in hindsight, more should have been done to protect the vulnerable shorelines. Most important, government supervision of off-shore drilling was a joke. But this is not "Obama's Katrina", as put about by Republicans bent on extracting revenge for the hurricane disaster that doomed George W Bush's presidency.

That was incompetence, pure and simple. This time the federal government has performed respectably. The problem is that nothing it can do will make much difference. Obama is simply being overwhelmed by what can be termed the Cult of the Presidency: the knee-jerk reaction of the country to turn to the man in the Oval Office for reassurance and answers in any national emergency, as if he had superhuman powers. If he can't deliver, then heaven help him.

So it has been with the BP oil spill. This President, so recently lauded for his "no-drama Obama" deportment, is now criticised for being too cool, too lawyerly and too cerebral – as if teary Bill Clinton-sized dollops of "I feel your pain" could have put everything to rights.

That, of course, is not the Obama way. Public empathy, he would be the first to admit, is not something he does well. His instinctive reaction has been the cold fury of the rational man betrayed. Yes, he had made mistakes, he admitted at his press conference last week, most notably that "I was wrong to believe the oil companies had their act together when it came to worst-case scenarios".

But even if from the outset he had not trusted a word said by BP, what difference would it have made? Like it or not, the oil companies, not governments, have the technology that is supposed to cope with this sort of crisis. What was Obama to do, send in the marines? But the country expects the President to take charge, and all the more so on this occasion, given that the chief villain of the piece is a foreign company. Thus the sorry spectacle of the White House insisting it was directing the response, that it would continue to "keep its boot on the neck of BP". In reality it could be no more than a spectator as the company's previous efforts to plug the well failed.

Back in the 1930s, Stanley Baldwin accused Fleet Street's newspaper proprietors of "seeking power without responsibility, the prerogative of the harlot throughout the ages". Thanks to the 21st-century Cult of the Presidency, Obama is saddled with exactly the opposite problem – and the worst nightmare of any politician – of responsibility without power. Do something, anything, they implore him; some even propose that a modest underground nuclear explosion could do the trick. After all, a president can solve any problem, can't he?

If anything the cult has grown since Bill Clinton's day. First, in the guise of the "war on terror", Bush and vice-president Dick Cheney enlarged the powers of the executive branch, at the expense of Congress. Then Obama took office in economic circumstances so dire that bigger government was inevitable. Equally inevitably, the aura of the White House grew further during the last decade, irrespective of the results achieved.

The real question now is whether Obama will be spared a protracted humiliation that might cost him not just heavy losses for his party in November, but his own job in 2012. That fate after all befell Jimmy Carter, when the Iranian hostage crisis hijacked the last 15 months of his presidency. Carter's projection of weakness, above all in the botched rescue attempt of April 1980, was the main reason for his defeat.

Could the same happen to Obama? Probably not, even though the cult of the presidency is far stronger than it was 30 years ago. Even if BP's current "top hat" operation fails to contain the leak, experts seem to agree that two relief wells will definitely do so, once and for all, when they are completed in August. By then, moreover, something else will have captured the media's attention.

But don't count on it. The effects of the spill will surely wreck the summer tourism season on the Gulf, and may play havoc with the even more important winter holiday season in Florida. And then there's the weather, which even presidents can't be expected to control. A fierce 2010 hurricane season is expected; the damage another Katrina and hundreds of thousands of barrels of escaped crude might wreak is too dreadful to contemplate.

Ultimately some good may come of this man-made tragedy in the Gulf: proper regulation for an oil industry and maybe – but don't hold your breath – energy legislation that seriously seeks to break the national addiction to oil. As for Obama, he will be reflecting, impotently, on the words attributed to a 20th-century British prime minister. "Events, dear boy..."