During his controversial presidency George W. Bush has faced a variety of issues that could be addressed from an ethical standpoint, from the environmental concerns of the Kyoto protocol to the conflict in Iraq. But is Bush acting morally or pragmatically in what he believes to be US interests? John Gray and Peter Singer lock horns over what really makes the world's most powerful leader tick.

It would be nice to think that George W. Bush's ethical views make no difference to the world. Unfortunately, they do. As the only global superpower, the US has a moral responsibility to act as a good global citizen. Under Bush's leadership, it has failed to do so.

Take climate change, for a start. With less than 5 per cent of the world's population, America produces more than 30 per cent of the world's greenhouse gases, making it the largest contributor to the problem of global warming. All the other major industrial nations agreed to meet the targets set by the Kyoto protocol. Bush said he would not. (This has led Russia to back away from ratifying its decision to sign the treaty. But there can be little doubt that if the US had accepted the Kyoto protocol, Russia would also have done so.) Defending his decision, Bush said that the Kyoto protocol was not "even-handed" because it did not bind China and India. This shows a warped sense of fairness, for the US produces roughly six times as much carbon dioxide, per capita, as China, and about 15 times as much per capita as India. Asked whether the President would call on drivers to sharply reduce their fuel consumption, the White House Press Secretary replied: "That's a big no. The President believes that it's an American way of life, and that it should be the goal of policy-makers to protect the American way of life.

The American way of life is a blessed one."

A franker statement of immoral national selfishness would be hard to imagine. America is in effect appropriating a giant slice of a common resource - the capacity of the atmosphere to absorb our waste gases - to which it has no claim. And it is taking it from poorer nations that are much less well equipped to cope with the consequences of climate change than the wealthy nations. Bush's policies could, in decades to come, result in millions of deaths from drought in sub-Saharan Africa, or floods caused by rising sea levels in Bangladesh - all to preserve the rights of Americans to drive big, thirsty four-wheel-drive vehicles.

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A similar disdain for other nations can be seen in Bush's attitude to the International Criminal Court. This initiative, to which more than 90 nations have acceded, seeks to establish a global enforceable law against crimes against humanity and genocide. Bush's administration has refused to join the court, and has sought to undermine it by suspending military aid for 35 nations that refused to pledge to give American citizens immunity from the court's jurisdiction. From the start, this looked as if Americans thought they were above the law. It became truly breathtaking hypocrisy when the Bush administration began holding hundreds of foreigners in detention in Guantanamo Bay without granting them access to a lawyer or bringing charges against them. These prisoners have now been held captive for more than two years. Is that America's idea of the rule of law?

All this is part of a pattern that came to a head when Bush proclaimed the right to "take the battle to the enemy, disrupt his plans, and confront the worst threats before they emerge". This "Bush Doctrine" flouted the role of the United Nations in resolving international disputes and justified aggressive action on the basis of a perceived, but unproven, threat to American security. Confident in his faith that America is good and its are enemies evil, Bush has led his country into a war that has already cost thousands of lives, with more dying every day. It is a war that has almost certainly done more to strengthen al-Qaeda than to weaken it.

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Some might say that for all his talk about good and evil, Bush is simply acting on the basis of national interest. He did seem to take this line when, as a candidate for the presidency, he spoke about foreign policy and said that the US should be "humble" and not get involved in countries where its vital interests were not at stake. But after the events of September 11 2001, he seems to have believed that he has been "called" to be president at this time. As recently as April 14 he described freedom as "the Almighty's gift to every man and woman in this world" and suggested that he was doing God's work in bringing freedom to the Middle East. That is an ethical view, but a dangerously simplistic one.

Peter Singer is the author of The President of Good and Evil: Taking George W. Bush Seriously , published by Granta, ?8.99.

John Gray and Peter Singer will debate "The ethics of George W. Bush: good, bad or irrelevant?" at the National Portrait Gallery on May 20 at 7pm.

"Embalm a modern artist and give beauty a chance", the last Controversial Thesis debate, will be held at the National Portrait Gallery on June 17 at 7pm. Donald Kuspit will propose and Norman Rosenthal will oppose. For tickets, call 0207 306 0055 ext 216.

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