Even in Opposition, David Cameron benefited from his prime ministerial appearance. Indeed, this is probably what speeded him to victory in the Conservative leadership ballot – that, and the confidence to pace the conference stage and deliver his candidate's speech without notes. When he subsequently entered No 10, as he always seemed destined to do, he looked as though he had passed through that famous front door every day of his life.
The few days that Cameron spent in the United States this week, however, afforded glimpses of someone a little different. Descending the aircraft steps on his arrival, the Prime Minister looked slightly nervous. So assured at home, he seemed not quite certain what expression to adopt while the national anthems were played. The jeans – what is it with British prime ministers, US visits and jeans? – did not do much for him when he set off that same evening on Air Force One for the basketball game in Ohio.
As for the joint interview he gave at the sports stadium alongside Barack Obama, the disparity in power between a British prime minister and a US president at the start of the 21st century was all too graphically on show. Obama was relaxed and in charge; Cameron was quiet, pale, uptight and very, very English. And if the excuse is that it had been a long day and Cameron was tired, that is what national leaders have advisers for, to make sure they do not land themselves in such predicaments.
This other aspect to Cameron, however, highlights an under-appreciated fact: Cameron was brought up to be an Englishman, and he has naturally become a very English prime minister, with all the pluses and minuses that entails. He is at home in Westminster, in the City, in his Oxfordshire constituency and elsewhere in the Shires. He does not always travel well.
That this is only now becoming apparent, almost two years into his prime-ministership, may have several explanations. It was his good fortune to follow Gordon Brown, a man whose crumpled self-deprecation and residual Scots accent never really made him convincing, image-wise, as Prime Minister. And Tony Blair, for all his huge first parliamentary majority, was always handicapped by a certain lightness of manner entirely consonant with the verbal slipperiness that later defined him. Superficiality in his deft hands became modernity, promoted as Cool Britannia.
Cameron had an advantage over both his predecessors. His bearing, the authority of his speech and his much-remarked upon sense of entitlement restored the requisite decorum to the post. Contentment seemed to settle over the land, as though the country had found a prime minister worthy of it, and of the job title. You knew he would never dream of wearing a donkey jacket to the Cenotaph. He understood how to behave. Scarcely had he got his feet under the desk than the word went around that his colleagues and, more to the point, his civil servants were impressed with his approach. He did not obsess about the detail; he knew how to delegate; he got a good night's sleep. So comfortable did he appear, in fact, that one commentator recently – Max Hastings in the Financial Times – described him as "too casual for his own and our good".
In a way, though, that observation harks back to the question that has lurked since Cameron's earliest political days. The appearance may convince, but how much substance lies behind it? Is a privileged upbringing and the polish bestowed by Eton and Oxford all there really is? Worse still, are confidence and cachet the only qualifications a British prime minister needs – public relations, in fact, by another name?
The answer to such questions was probably always No. But it has to be a far more definite No in this day and age, as this past week has shown. Cameron may have consummate manners and know how to behave, but he remains quintessentially English – too English, perhaps, for his own political good.
In the United States – a country bursting with people just as self-confident as Cameron usually appears – his unease came through at times when it could not be masked by formality. We have not seen Cameron that often, or so close up, on other foreign visits – and taking a plane-load of business people with him, as he is wont to do, helps to protect his natural habitat. But his petulant veto at the EU summit before Christmas may also have its genesis less in a desire to please his eurosceptics than in that peculiarly English lack of cultural sensitivity from which euroscepticism derives.
Coincidentally, it was that very same insular Englishness that was identified earlier this week as an electoral handicap for the Conservatives in the North of England. Eric Ollerenshaw, MP for Lancaster and Fleetwood and an aide to the party's co-chair, Baroness Warsi, said the party's electoral chances could be damaged by northern voters who saw the party's leadership as made up of "southern, posh white men who are not one of us". As a description of Cameron, as seen from north of The Wash, such a catalogue rings painfully true.
For the world at large, Cameron has a not-so-secret weapon in the shape of his Coalition partner and deputy, Nick Clegg, and he has deployed him skilfully. Cosmopolitan, multilingual, and as perfectly mannered as he is, you really can take Nick anywhere. He is as much of an asset to Cameron on the world stage as, say, Prescott was for Blair in the Labour heartland, or Willie Whitelaw for Margaret Thatcher in the Shires. But there are times – an official visit to the US, or a crucial EU summit – when a deputy will not do. And as Clegg's difficulties with his Sheffield constituency show, the North is not really home turf for him either.
One consolation for David Cameron might be that the five hours he spent on a plane with Obama and the two more they spent together in the Oval Office apparently convinced the US President that there is more to the Prime Minister than southern, white, English poshness. That suggests the Tories might benefit if Cameron were to circulate more beyond his domestic comfort zone.
Such a tactic, though, would carry a risk: that unless he can make himself less stereotypically English, voters' prejudices might only be confirmed. In that case, his electoral prospects might be better served by rethinking his opposition to Scottish independence and embracing his future as an unapologetic English prime minister.