Once a single journalist could speak for the whole of America. Last week an extraordinary editorial in the New York Times demonstrated the limits of the press in a diffuse media age. Paul Harris reports

It was a journalistic moment that harked back to an older age of the power of print. The venerable New York Times, one of the world's most famous newspapers, was delivering a devastating verdict on the war in Iraq. American troops should leave, it declared. In a stark editorial, it called for withdrawal from Iraq, essentially announcing that the war had failed and that the troops needed to come home as soon as possible.

It was a potentially historic stance by the most powerful institution in American print journalism. In an interview with The Observer, the paper's Editorial Page Editor, Andrew Rosenthal, laughed when asked how long the decision to call time on the Iraq war had been in the works. 'Four years,' he said.

The editorial set off a firestorm of debate, prompting both outrage and support. Some portrayed it as Iraq's 'Cronkite moment', comparing it to the famous broadcast when legendary TV newscaster Walter Cronkite came out against the Vietnam war.

But the real story of the New York Times editorial lies not in what it said about the conduct of the war in Iraq. It lies in the way it exposed the nature and role of the media in covering that war. Whereas Cronkite's huge profile was able to influence the national debate on Vietnam, the modern media world is a far more fractured place. In fact, the main impact of the editorial was to trigger a fight in the media, not a debate over Iraq policy. Far more than in the 1960s, the modern American media landscape is divided into warring tribes who seem to spend at least as much time attacking each other as attacking the administration of the day.

The reaction of conservative media was ferocious, with many saying that the paper was embracing American military defeat. The Washington Times said the paper was part of an 'appeasement caucus'. Fox News TV presenter Bill O'Reilly went further. He lambasted the paper as having 'declared defeat' in Iraq. 'So there is joy in far Leftville,' he blustered. But perhaps nowhere was the venom heaped on the newspaper more poisonous than on right-wing blogs. 'I liked the NYT better when it had a liberal bias, rather than the current bias in favour of the Islamic right,' one commenter said.

On the floor of the Senate, Republican presidential hopeful John McCain stood up and tried to rebut the editorial point-by-point. He said that the paper did not understand the purpose of the war. 'According to the New York Times, it is not worth fighting to prevent genocide,' he said.

For Rosenthal, the reaction was expected and profoundly misplaced, especially the criticism that a withdrawal of American troops would lead to bloody civil war: 'The spin from the right now is that we are aiding and abetting a genocide... but the fact is that what's happening in Iraq is not going to be a consequence of America leaving, it is going to be a consequence of the American invasion of Iraq in the first place.'

Neither was it only the right that heaped it on the New York Times. The attacks from some on the left, especially in the increasingly influential world of liberal bloggers, were equally tough. Many took the line that the paper was far too late in finally deciding to call for the troops to come home. Others used it as an excuse to again attack the paper for its coverage of WMD issues before the war, especially by the now discredited reporter Judy Miller.

'A lot of them wrote that all this is because of Judy Miller, which is ludicrous. The degree to which Judy Miller was responsible for our coverage of the run-up to the war has become just propaganda,' Rosenthal said. 'It is absurd.'

But there was no doubting the tone of the editorial. The New York Times was firmly coming down on the anti-war side of the barricades, a place from which there can be no reverse of position.

It basically consisted of a single sentence separated out at the top of the article under the headline: 'The Road Home'. It read: 'It is time for the United States to leave Iraq, without any more delay than the Pentagon needs to organise an orderly exit.' There followed a lengthy piece detailing the analysis behind that simple but devastating indictment.

Rosenthal said the piece had been in the works for at least three weeks, being edited and revised, but that it was the culmination of a much longer process of working out the newspaper's thoughts on the conflict: 'We have been talking for months about taking the next step.'

The importance of the New York Times's move was swiftly revealed as a host of other newspapers followed suit. Alabama's Tuscaloosa News and the Olympian in Washington State also called for the withdrawal of US troops. 'Americans have had it with the war,' the Olympian said in its editorial. An April survey showed that only 28 per cent of Americans approved of the handling of the war.

But, though the New York Times rejection of the war has created the most media heat and light, its influence is far from what it used to be. The fact is that the paper has come relatively late to the withdrawal position. Smaller newspapers have previously taken that stance; in May the Los Angeles Times - one of the biggest papers in America - urged a pullout under the headline 'Bring Them Home'.

Yet the power of newspapers to influence political policy is greatly decreased in an era where the greatest political pressures seem to come from cable news channels and the internet, via blogs or YouTube.

'The time when you could have a "Cronkite moment" has passed,' said Professor Jack Lule, a media expert at Pennsylvania's Lehigh University. 'I think the New York Times would have liked that last week, but that was a very different era.'

The modern media world is one in which no organisation - whether it be a single newspaper or a broadcaster - can make any claims to dominance. Whereas Lyndon Johnson famously declared that 'If I've lost Cronkite, I've lost Middle America', George Bush has made a virtue of his self-confessed ignorance about what the media is saying about him, especially newspapers such as the New York Times

Rosenthal thinks that some of that is bluster. 'The White House tells us they don't read us, but someone in the administration must do, because they always seem to know what we've been saying,' he said.

But experts say the media world has changed so much since the 1960s that the White House analysis is largely correct. The attack dogs of the traditional press have been largely defanged by a new media world.

'Before, this story would have led all the news bulletins for a week,' said Lule. 'That is not the case now. The New York Times has become just one voice in the media matrix.'

Even Rosenthal admits that the paper is perhaps not the influential voice it once was. He acknowledges that in the end it is the White House - not newspaper editorials - which will set future Iraq policy: 'I hope it affects the debate. But the turning point has to come from the White House, not the New York Times.'

That moment looks as if it could still be a long way off.