Leading article: Mr Obama makes his case for a historic rapprochement

It is not often in modern times that a single speech is delivered with a view to changing history; still more rarely that it achieves this end. But the address delivered by the US President at the University of Cairo yesterday has a chance, just a chance, of doing that. If the United States and the Islamic countries eventually succeed in banishing their mutual suspicion and inaugurating a new age of understanding – a distant prospect, to be sure – Barack Obama's bold efforts to make a new beginning, based, as he put it, on mutual interest and mutual respect, will deserve much of the credit.

As a President seeking to bridge the gulf that now yawns between the United States and the Islamic world, Mr Obama started out with three advantages. The first derived from his biography. His references to his Kenyan family, his childhood in Indonesia and his Chicago years all rang true. The second, not unconnected, is the cultural sensitivity that derives at least in part from that variegated background. When he quoted from the Koran – as he did several times and always to applause – the allusions flowed naturally, without the slightest affectation. And the third is his skill as a communicator, which encompasses not just his formidable rhetorical gifts, but his ability to explain a complex message in such a way that it will be heard and understood. These qualities, which played such a large part in winning him the presidency, were displayed to full effect again yesterday.

Nor were any of the intended recipients left with any excuse for misinterpreting what he had to say yesterday. Not only was the speech widely trailed by the US administration, it was also webcast live by the White House and supplied via text messages in Arabic, Urdu and Farsi translation, with invitations for the recipients to comment.

The speech was as pitch-perfect as we have come to expect from Mr Obama. But in content, too, it was hard to fault. This was an hour-long discourse on subjects that have been minutely analysed and argued about by experts over the years. It was a diplomatic and intellectual tour de force; a cool, logical and coherent argument for the ditching of stereotypes and the harmonious coexistence of two different, but not automatically conflicting, views of the world.

The US President had some uncomfortable things to say: to Israel about calling a halt to the settlements and accepting a Palestinian state; to Palestinians about not launching rocket attacks on Israel; to the whole Arab world about recognition for Israel and the permanence of the US-Israel alliance, and to conservative Muslim states about the place of women. But he did so in a way that made clear that he was representing American interests and that the US, during his presidency at least, had no claims on other people's territory, security or way of life.

It is true, as a few less benevolent critics noted yesterday, that words are not the same thing as deeds. But words set a tone, and Mr Obama's every nuance was calculated to say that today's White House, politically and philosophically, is as far from George Bush's as it is possible to be. A time will come when Mr Obama – and the US public on his behalf – will, rightly, expect his outstretched hand to be reciprocated. Foreign leaders will not be able to bask indefinitely in the US President's reflected goodwill. But this month sees crucial elections in Lebanon and Iran, and all leaders need to carry their people with them. If patience is the price of a new start in US-Muslim understanding, Mr Obama can afford to wait.