Barack Obama's speech on NSA surveillance was in many ways the Democratic president at his best and the United States at its best too. George Bush would certainly not have made the speech. Nor, arguably, would Bill Clinton. What is more, no modern British prime minister of either party would have come anywhere near it. And no Chinese or Russian leader would even think of such a thing. It would be hard to imagine, outside the realm of Hollywood fiction, a more balanced and serious response to the vexed issues of security and privacy abuse than the one Mr Obama offered today .

This is not in any way to cast the speech as ideal. Mr Obama has presided for five years over the discredited and omnivorous data surveillance system that he now proposes to reform. Behind the charismatic rhetoric lie many important practical questions – like the immense issues about text message metadata reported in the Guardian today – that were not addressed. Several central problems, such as metadata storage and reforms to the foreign intelligence surveillance court, have been passed to Congress and officials for more detailed work, which may produce inadequate outcomes. Some may dispute the necessity for US security surveillance programmes at all, though this is absolutely not the Guardian's view. In the real world, Mr Obama's speech counts as a big step forward in responding to the issues of security and privacy raised by the era of diffuse terrorist threats and the revolution in cyber-technology. Such a response is overdue, which is essentially why Edward Snowden did what he did. Mr Obama was able to produce that response partly because the US is at the centre of these global issues, partly because he has the calibre and instincts to treat all the principles seriously, but also because, only months after the Snowden revelations, the US system of government has proved it has the heft, the nerve and enough grounding in democratic accountability to rise to the occasion.

The contrast between America's serious response to the challenge of the Snowden documents and the response from the British political system could hardly be starker. In the space of eight months, Congress has exerted pressure, the president has set up a review, the review has been completed and then – today – the president has changed the rules. Yes, there are inadequacies in that response too. But it is manifestly a process of accountability and responsible statecraft at work. In Britain there has been almost nothing of the sort. There have been minimal debates, little scrutiny, no proper review of any kind, and David Cameron has barely addressed the issues. America's political system is doing its job. Britain's is failing.

Mr Obama made the same case for sustained intelligence gathering in the modern world that a British leader would make. But he also addressed what he called "the risks of government overreach" in ways that no Labour or Conservative leader has yet faced up to. Mr Obama admitted that routine communications around the world are in the NSA's reach and that this is disquieting. Mr Cameron has said nothing about this. And Mr Obama began to acknowledge some of the damage that overreach does to his country's reputation abroad and with allies. Britain remains astonishingly blind to the equivalent harm done here.

Two particular sentences in the speech underscore the transatlantic gulf. All of us understand that the standards for state surveillance must be higher, the president said. It is not enough, he went on, for leaders to say: trust us, we won't abuse the data we collect. By saying this, not before time, Mr Obama opens the door into a room in which security and privacy can both be properly valued and defended. In Britain, that door remains locked and barred by government. It is time to open it here too.