Al Jazeera, the hugely influential, Qatar-based, Arabic-language satellite news channel, has replaced its high-profile news director, Wadah Khanfar, on the back of WikiLeaks revelations that he toned down the station's Iraq coverage in 2004 and 2005 in direct response to criticism from American officials.

Copies of critical reports of the station's coverage, drawn up by the US Defence Intelligence Agency, were, according to the cables, frequently handed over to an apparently all-too-compliant Mr Khanfar.

However, for anyone who has closely followed Al Jazeera's output over the years, the latest revelations merely confirm what has long been known.

Back in 2003, just after Mr Khanfar was appointed, I reported that Al Jazeera agreed to pull two cartoons from its Arabic- and English-language websites that had been deemed "inflammatory" by US officials.

One was of young Latino men shown going through an immigration tunnel to emerge from the other side ready to leave for military service in Iraq. The other was of the Twin Towers imploding, and two giant fuel pumps rising to replace them.

There has been a steady leak of similar stories since, giving ammunition to critics of the station's claims to objectivity. But Mr Khanfar's position had never before appeared to be under threat.

So why has he now been deemed expendable? The timing of the WikiLeaks cables was everything. Al Jazeera was launched in 1996 with one aim: to put Qatar on the map. While ultimately run by the island's ruler, Sheikh Hamad bin Thamir Al-Thani, its coverage of regional issues was bolder than anything seen before in the Arab world.

But now it has served its purpose. Qatar is known internationally. It will host the World Cup in 2018, and has used its huge gas-generated income to gain leverage, from Libya to Egypt, in the fallout from the Arab Spring.

Al Jazeera has also been crucial to the success, or otherwise, of the regionwide uprisings. Its coverage of the Tunisian and Egyptian revolutions proved crucial in the ousting of both countries' dictators. Its tamer coverage of unrest in Bahrain and Yemen, in keeping with a Saudi-Qatari counter-revolution in favour of the status quo, has helped keep those the revolts out of the headlines.

In short, Al Jazeera's often sensational, but always powerful and unpredictable, coverage of Arab affairs has become a hindrance to Qatar's efforts to ingratiate itself with Western powers and contain further revolts.

The replacement of Mr Khanfar as news director by a member of the Qatari ruling family, rather than an attempt to restore the channel's reputation for objectivity and professionalism, actually marks the abandonment of any such pretensions.

That will be music to the ears of the US and its regional ally, Israel, whose strategic interests are threatened by continuing unrest in the Arab world. But it is yet more bad news for the spread of democracy in the region.

'After the Arab Spring' by John R Bradley is forthcoming from Palgrave Macmillan