Many Americans will see the backlash against Aznar as a victory for Al-Qaeda or further evidence of the limp-wristed nature of European allies. But the fact that it happened in the country in Europe that is most sensitized to terrorism should give them pause for thought. The reasons the Spanish did not treat the terrorist outrage with their usual reserve need to be studied – and understood – if America is to preserve its few remaining friends. And the furious debates that are raging in London, Rome and Warsaw – who are all asking if they will be next – are shaped by the same issues that troubled their Spanish neighbors.

First, all Europeans saw the Iraq war as a “discretionary war” – one we chose to fight rather than a classic war of self-defense (and many questioned the link between Iraq and terrorism). One of the consequences of getting involved was to put ourselves in the firing line. It is easy for Americans, who are already targets for global terrorism, to see a reluctance to get involved as cynical cowardice – an echo of Munich in 1938. But it is legitimate to note that the threats to Europeans and Americans were not analogous – how many bombs would have gone off in Madrid if Aznar had not supported the war in Iraq? Even in Britain, America’s staunchest ally, leading voices warned of the risk of becoming a magnet for terrorism by supporting the war. In the run up to the war, Kenneth Clarke MP, the former finance minister and one-time candidate for leader of the Conservative Party, opposed military action: “We should avoid it because of the consequences of war. How many other terrorists will we recruit? Next time a large bomb goes off in a western city, [we will be asking] how far did this policy contribute to it?”.

Secondly, there is the issue of trust – and the way the controversy over the case for war has contaminated the relationship between political leaders and their citizens. In an editorial entitled “Of Lies”, the leading Spanish newspaper, El Pais, declares that it was “the manipulation, the lies, the offensive use of the argument of the war against terror to justify just about any policy, the blatant opportunism and puerile arrogance that caused those in power to lose it yesterday”. The controversy over WMD and terrorism became linked with the PP’s attempts to pin the bombing on ETA, rather than Al Qaeda. The Crowds gathering outside the Socialist Party’s headquarters to celebrate were united in a chorus of ”Ganamos sin mentiras!” (We have won without lies). The same issues have spread to Britain. Tony Blair, the most trusted political leader in British history, has had negative trust ratings for over a year. His concern over the corrosive impact of Iraq was captured with brilliant economy in the diary of his former spin doctor Alastair Campbell: “It was grim, grim for me and grim for TB [Tony Blair], and there was this huge thing about trust”.

Third, political leaders in Europe are treated as “just politicians” – rather than as father-figures who unite the nation. The dual role of the American President – as head of state and CEO – often leads to a rallying at times of national crisis. The extraordinary political unity that came over America after 9/11 shocked many Europeans who thought that America became a country incapable of political dissent. The brutal retribution handed out by Europeans to their leaders in times of crisis will no doubt shock Americans. This has more to do with a difference in our constitutions that our temperaments or values. In many European countries there is a division of labor. The Prime Ministers head the governments and take the flack when things go wrong. The Heads of State (monarchs in Spain and Britain, Presidents in Italy and Poland) stand above the political fray and unite the nation.

If 9/11 changed America, it was the Iraq war that changed Europe – and left all the US allies looking very exposed. At the top of the “least-wanted” list is the Italian leader Silvio Berlusconi who, like Aznar, defined his countries’ public opinion and political establishment to support the American intervention. With his right-of-centre Casa delle Liberta government expected to suffer losses in the June European Parliament elections, and with the possibility of a general election by the end of the year, he must be a very worried man. In Britain and Poland, where the main political parties and a majority of the public supported the Iraq war, a terrorist attack is unlikely to force Blair or Miller out of office.

But the fall-out from Spain will affect these countries too and make support for Bush ever-more difficult to rely on. Unless there is a major re-haul of the Administration’s approach to unilateralism and “ally-diplomacy”, the people in the Whitehouse will not just see the four European friends they had at the beginning of the year reduced to two. They might find that nobody is left at all.

Mark Leonard is a transatlantic fellow with the German Marshall Fund of the United States and founder of European think tank, the Foreign Policy Centre.