Official press conferences of any kind seldom produce real news, but the worst are usually those given by foreign leaders on trips abroad in which they and their local ally suggest that they are in control of events and all is going according to plan.
One of the many infuriating, though also ludicrous, events in Iraq since the invasion of 2003 has been American and British leaders, arriving in secret at the enormous US base at Baghdad airport and travelling, accompanied by numerous armed guards, by helicopter to the heavily-fortified Green Zone. After a few hours there they would give upbeat press conferences, sitting alongside the Iraqi leader of the day, claiming significant improvements in security and chiding the assembled journalists for ignoring such clear signs of success.
Periodically reality would break in, such as the time a mortar bomb exploded nearby the press conference hall at the very moment when UN Secretary General Ban ki-Moon was lauding security improvements, compelling him to cower down behind a display of artificial flowers.
Visiting US politicians during the presidential election sought determinedly to manicure what American television viewers would see. Diplomats at the US embassy complained that staffers of Republican candidate Senator John McCain had asked them not to wear helmets and body armour when standing next to him in case these protective measures might appear to contradict his claim that the US military was close to military victory.
For similar reasons staffers of the Vice President Dick Cheney demanded that the siren giving a seven or eight second warning of incoming rockets or mortar rounds to people in the Green Zone be turned off during his visits.
I used to comfort myself with the thought that these official visits did little harm even if they did no good. Iraqis were all too aware of the grim reality of their lives to be taken in by official posturing. After five years of war, American voters have seen too many claims of success in Iraq deflated by news of fresh slaughter to be deceived into thinking that the war was being won.
In retrospect I think I was over-optimistic: the foreign leaders who visited the Green Zone or other US or British military camps came away with the dangerous idea that they knew something about Iraq. They would depart not realizing that the most important political fact was that the majority of Iraqis detested the US-led occupation whatever they thought of Saddam Hussein. Even the foreign minister Hoshyar Zebari, widely seen as pro-American called the occupation "the mother of all mistakes". This explains the popular enthusiasm for Mr Zaidi on display in Baghdad yesterday.
The history of the Iraqi occupation is now beginning to feel like ancient history but it is relevant because the US and Britain are committing elsewhere so many of the same mistakes as they did in Iraq. Just at the moment when Mr Bush was dodging footwear in Baghdad, accompanied by the Iraqi prime minister Nouri al-Maliki, Gordan Brown was appearing with the Pakistani president Asif Ali Zardari in Islamabad.
Mr Zardari is seen as a weak leader, uncertain of what he should do and with limited authority over the military. But, as in Iraq in the past, his constant appearance besides visiting foreign dignitaries convinces Pakistanis that he is a US puppet. The constant finger-wagging against Pakistan by Mr Brown, the US secretary of State Condoleezza Rice and others may do something to encourage the Pakistani government to act against organizations like Lashkar-e-Toiba and its civilian arm Jamaat-ud-Dawa. But it also encourages a sense in Pakistan that it is being besieged, encircled by India to the east and a pro-Indian Afghan government to the west.
The US drone attacks on Pakistani territory increase this fear of military encirclement.
One does not have to spend long in Pakistan to discover that many Pakistanis, perhaps a majority, dislike the US more than they do India. It is all very well for Mr Brown to call for "action not words" against terrorists in Pakistan but this is a truly impossible task even if President Zardari were a leader of real authority. The US and the Iraqi government, with vast resources at their disposal, have failed to eliminate al-Qa'ida in the heart of Baghdad where there are regular suicide bomb attacks and assassinations.
I visited the Jamaat-ud-Dawa headquarters in Lahore just before it was closed last week and its members exuded confidence that nobody was going to put them permanently out of business. State authority in Pakistan is eroding by the day. In Peshawar, the city at the mouth of the Khyber pass through which flow 75 per cent of supplies to western forces in Afghanistan, several hundred well-armed gunmen have calmly taken over depots filled with US military vehicles and burned them to the ground.
At this point somebody is bound to suggest that Pakistan is a failed state without realising that they are entering dangerous ground. Foreign Policy magazine in Washington does an annual survey of supposedly failed states in which Pakistan is ranked number nine in 2008. But a failed state does not necessarily a mean a weak country or a society unable to defend itself. It is precisely in such allegedly failed states as Lebanon, Somalia and Iraq that the US has suffered its greatest foreign policy disasters over the past quarter century.
One small lesson of the debacle in Iraq might be to cut back on these official visits such as those by Mr Bush and Mr Brown last Sunday. In Islamabad Mr Brown's demand for a crack down on terrorism makes any action taken by the host government look as if it is cravenly acquiescing to a foreign power. In Baghdad Mr Bush could see for the first time in five years, in the shape of pair of shoes hurtling towards him, what so many Iraqis really think of him.
Patrick Cockburn is the author of 'The Occupation: War, resistance and daily life in Iraq', a finalist for the National Book Critics' Circle Award for best non-fiction book of 2006. His new book 'Muqtada! Muqtada al-Sadr, the Shia revival and the struggle for Iraq' is published by Scribner.