Although few America-haters resort to terror, their simmering rage not only incubates violence; it also provides the moral support that can transform a crime against humanity into the opening salvo of a political, religious, cultural and economic struggle. Thus there is a need to understand it better.

Anti-Americanism's most frequent expressions usually reflect a mish-mash of grievances. But one can identify five types: politico-economic, historical, religious, cultural and psychological.

Politico-economic anti-Americanism represents a reaction to current US foreign policies: support for Israel or for repressive governments in the Middle East; the US's role in the Balkans; its embargo on Iraq and Cuba; the lack of support for the Kyoto protocol on climate change or for the establishment of the international criminal court. US economic policies also draw fire, whether for limits on imports from poor countries or for the use of the International Monetary Fund and World Bank to advance US interests.

Historical anti-Americanism has its roots in past US behaviour. In a column titled "The Last September 11", Ariel Dorfman, a Chilean novelist, reminds his readers that on September 11 1973 the democratically elected government of Salvador Allende, the Socialist president, was overthrown in a military coup backed by the US. "Both in Chile in 1973 and in the States today, terror descended from the sky to destroy the symbols of national identity, the palace of the presidents in Santiago, the icons of financial and military power in New York and Washington." Similar sentiments are common in many other countries.

Religious anti-Americanism is most virulently expressed by Islamic fundamentalists. In the words of Ayatollah Khomeini, Iran's late spiritual leader, "[Americans] are the great Satan, the wounded snake." But religious anti-Americanism is by no means exclusively Muslim. Roman Catholic liberation theologists, Greek Orthodox prelates, fundamentalist Jewish rabbis and US televangelists also condemn American society's "corrupting immorality".

Cultural anti-Americanism is stirred by the ability of the American way of life to influence and often displace local cultures. Satellites that beam US television overseas and commercial brands that attract billions of consumers also stoke anxiety and anger about cultural invasion. The list of American realities that jar the sensibilities of citizens in other countries is long: women's rights, sexual permissiveness, drug use, gun ownership, the death penalty, intrusive marketing, fast food, tolerance for economic inequality, racism and high incarceration rates.

Psychological anti-Americanism is fuelled by jealousy, resentment, ambivalence and crushed expectations. The seductive allure of American capitalism, freedoms, products and culture often co-exists with ambivalence about them as being economically or politically unattainable.