Like it or not, the spectre of Vietnam has haunted the invasion of Iraq and its aftermath. George W Bush, in an interview last year, said that “the thing about the Vietnam war that troubles me, as I look back, was it was a political war”. The lesson was not to have “politicians making military decisions”. In Iraq that is exactly what has been happening and the result has been chaos.

America’s Vietnam failure was laid at the door of Robert McNamara, defence secretary under Kennedy and Johnson, who took personal charge of the campaign, as Donald Rumsfeld, Mr Bush’s defence secretary, has done in Iraq. Mr Rumsfeld froze out others in the administration, refusing even to return their calls. He had little time for the joint chiefs of staff, accusing them of not offering “added value”. He ensured, like McNamara, that bad news was kept from the president.

As Bob Woodward recounts in his book State of Denial, which we serialise today, Mr Rumsfeld was warned early on about the mistakes being made. Jay Garner, the retired general put in charge of ensuring Iraq’s post-war transformation to stability, warned him that “de-Ba’athification” — banning members of Saddam Hussein’s party from official positions — was driving resistance underground. These and other criticisms went no further. If the picture that emerges of the defence secretary is of a misguided control freak, that which appears of the president is of an incurious man living in a bubble.

Yesterday was a relatively quiet day in Iraq. “Only” 15 people were killed, eight of them when a suicide bomber struck an army checkpoint. The bodies of more victims of sectarian death squads were discovered. But a crunch point is coming. Senator John Warner, the Republican head of the armed services committee, says the administration should consider a “change of course” if the country has not been stabilised over the next two to three months.

Politically, a war that has claimed the lives of more than 2,700 US soldiers and which even optimists say is “drifting sideways” is causing severe collateral political damage. Mr Bush’s popularity is at a new low and the Republicans, apart from the self-inflicted wounds they have incurred on Capitol Hill, are looking nervously towards next month’s mid-term elections.

One possible change of course, set to be recommended by the Iraq Study Group (ISG) under James Baker, is to divide the country into automonous Shi’ite, Sunni and Kurdish regions. Condoleezza Rice, the secretary of state, stopped off in Kurdish northern Iraq before flying to Britain yesterday. The president is likely to listen to the advice of Mr Baker, an old ally of his father.

Clearly something must be done soon. Henry Kissinger has also been advising Mr Bush, saying “cut and run” is not an option and that “victory is the only meaningful exit strategy”. That is true, but there are victories and victories. The aim in Iraq is to leave a post-Saddam nation capable of governing itself. The present strategy is not achieving that aim.