Leading article: Five solid years, but still much to prove

It was five years ago today that David Cameron, standing as an outsider, was elected to lead the Conservative Party. Now, it seems in some ways as though he has held that job forever, so comfortable does he seem in the role and so smoothly has he graduated from Opposition leader to Prime Minister. Yet he still seems the fresh new leader who bounded on to the stage and captivated his party conference with a pitch-perfect candidate's speech, delivered extempore. He remains youthful, engaging, and yes, to an almost infuriating degree, someone who was born to rule.

As a politician, Mr Cameron has also been exceptionally fortunate. Whereas everything Gordon Brown touched seemed to turn to dust once he had finally reached No 10 – including the economy, which had been his pride and joy – everything Mr Cameron touched, except England's World Cup bid, turned to gold. Even the personal tragedies – and we say this with no cynical intent – devolved to his political advantage.

Caring for a severely handicapped son gave him a human dimension and made him reliant on the NHS and other public services in a way that someone of his wealthy background might not otherwise have been. Ivan's sudden death accentuated his human qualities – and coincidentally removed a plank from the Liberal Democrats' planned election platform; they had intended to attack Mr Cameron for being remote from ordinary voters' concerns. The birth of his daughter, during the family holiday in Cornwall, not only produced stunning pictures, but helped quell pre-conference criticism of the coalition deal from inside his party.

Mr Cameron might be a fortunate politician, but he has also helped make that good fortune, with a shrewdly calculated embrace of risk. He decided to stand for party leader, and campaign as a moderniser, although David Davis was seen as the strong front-runner. He rewrote the agenda for the 2008 party conference at a moment's notice to take account of the financial crisis. His most conspicuous gamble, however, was his effort to turn the party's disappointing election result into a victory, by making his "big, open and comprehensive offer" to the Liberal Democrats, and making it boldly and in public.

So far, in his terms, that gamble has paid off. The country has its first coalition government since the war, and by and large the public has taken to the new politics, even if some of the party faithful on either side have not. In party political terms, the alliance with the Liberal Democrats has given Mr Cameron an alibi to be more liberal and less in hock to the party's right wing than he might otherwise have been. To date, largely because of the university fees issue, it is Nick Clegg, far more than Mr Cameron, who is feeling the heat.

In all, a positive report card for Mr Cameron, whose generally sunny disposition has also been an asset in these straitened times. The very ease with which he has taken to being Prime Minister, however, has the potential, if he is not careful, to turn into a liability. The Bullingdon air of being born to rule is never far below the surface. Fluency can tip over into glibness. And vultures are gathering around a host of policies, not just tuition fees, but timidity towards the banks and the malign effects of lower benefits, structural changes to the NHS and public sector cuts, whose wisdom is less evident to the many who will be affected than it is to the mostly privileged individuals on the front bench.

So far, from the Bloody Sunday inquiry to the birth of his daughter, Mr Cameron has shown perfect pitch. Public opprobrium has tended to slide off on to ministers, leaving him to glide serenely on. Suspicions that he is fundamentally a PR man and a lightweight persist. There are few certainties in government, but one is that good times rarely last.