Barack Obama says: "John McCain is determined to carry out four more years of George Bush's failed policies." Obama is a politician, so it's normal that he'd choose to repeat the lines that some of his followers want to hear. But before people buy that argument, I'd ask them to read three speeches.

The first was delivered by McCain on Sept. 28, 1983. The Reagan administration was seeking Congressional authorization to support the deployment of U.S. Marines in Lebanon. McCain, a freshman legislator, decided to oppose his president and party.

McCain argued that Lebanese society, as it existed then, could not be stabilized and unified by American troops. He made a series of concrete observations about the facts on the ground. Lebanon was in a state of de facto partition. The Lebanese Army would not soon be strong enough to drive out the Syrians. The American presence would not intimidate the Syrians into negotiating.

"I do not foresee obtainable objectives in Lebanon." He concluded. "I believe the longer we stay, the more difficult it will be to leave, and I am prepared to accept the consequences of our withdrawal."

This was not the speech of a man who thinks military force is the answer to every problem. It was the speech of one who conforms policies to facts. And it came a month before a terrorist attack that killed 241 Americans.

The second speech was delivered on Nov. 5, 2003. This was not a grand strategy speech. It was a critique of the execution of existing U.S. policy.

First, McCain wondered about the Pentagon's publicity campaign in Iraq: "When, in the course of days, we increase by thousands our estimate of the numbers of Iraqis trained, it sounds like somebody is cooking the books."

He then pointed out that the U.S. had not committed sufficient troops. He called for a counterinsurgency strategy in which U.S. forces would actually hold secure territory. "Simply put," he said, "there does not appear to be a strategy behind our current force levels in Iraq, other than to preserve the illusion that we have sufficient forces in place to meet our objectives."

He excoriated the arrogance of Paul Bremer and the Coalition Provisional Authority: "The C.P.A. seems to think that all wisdom is made in America, and that the Iraqi people were defeated, not liberated."

This was the speech of a man, adjusting to changing circumstances, who was calling on the administration to adjust quickly as well.

The third McCain speech was delivered on Wednesday. It is as personal, nuanced and ambitious a speech as any made by a presidential candidate this year.

McCain noted that we are not only fighting a war on terror. The world is seeing a growing split between liberal democracies and growing autocracies. We are seeing a world in which great power rivalries - with China, Russia and Iran - have to be managed and soothed.

Moreover, the U.S. is not the sole hegemon. Power is widely distributed among many rising nations. McCain's core purpose in the speech was to revive the foreign policy tradition that has jumped parties but that has been associated with people like Theodore Roosevelt, Henry Stimson, Dean Acheson, John Kennedy and Ronald Reagan.

In this tradition, a strong America is the key to world peace, but America's role is as a leading player in an international system. America didn't defeat communism, McCain said Wednesday, the American-led global community did. This is the tradition that Robert Kagan of the Carnegie Endowment has been describing for a decade.

McCain offered to build new pillars for that system - a League of Democracies, a new nuclear nonproliferation regime and a successor to the Kyoto treaty. In stabilizing Asia and the Middle East, he would rely more on democracies like Turkey, India, Israel and Iraq, and less on Mubarak and Musharraf.

Unlike the realists, McCain believes other nations have to be judged according to how they treat their own citizens. Unlike the Bush administration in its first few years, he believes global treaties cannot solely be evaluated according to a narrow definition of the American interest. The U.S. also has to protect the fabric of the international system.

McCain opened his speech with a description of his father leaving home on the day of Pearl Harbor, and then being gone for much of the next four years. He harkened back repeatedly to the accomplishments of the Truman administration.

In so doing, he signaled that the foreign policy debate of the coming months will be very different from the one of the past six years. Anybody who thinks McCain is merely continuing the Bush agenda is not paying attention.

But the key word is "together". We need to renew and revitalise our democratic solidarity. We need to strengthen our transatlantic alliance as the core of a new global compact - a League of Democracies - that can harness the great power of the more than 100 democratic nations around the world to advance our values and defend our shared interests.

At the heart of this new compact must be mutual respect and trust. We Americans recall the words of our founders in the Declaration of Independence, that we must pay "decent respect to the opinions of mankind". Our great power does not mean we can do whatever we want whenever we want, nor should we assume we have all the wisdom and knowledge necessary to succeed.

We need to listen to the views and respect the collective will of our democratic allies. When we believe that international action is necessary, whether military, economic or diplomatic, we will try to persuade our friends that we are right. But we, in return, must also be willing to be persuaded by them.

The nations of the Nato alliance and the European Union, meanwhile, must have the ability and the will to act in defence of freedom and economic prosperity. They must spend the money necessary to build effective military and civilian capabilities that can be deployed around the world, from the Balkans to Afghanistan, from Chad to East Timor.

We welcome European leadership to make the world a better and safer place. We look forward to France's full reintegration into Nato. And we strongly support the EU's efforts to build an effective European Security and Defence Policy. A strong EU, a strong Nato and a true strategic partnership between them is profoundly in our interest.

We all have to live up to our own high standards of morality and international responsibility. We will fight the terrorists and at the same time defend the rights that are the foundations of our societies. We cannot torture or treat inhumanely the suspected terrorists that we have captured. We must close the detention facility at Guantánamo and come to a common international understanding on the disposition of dangerous detainees under our control.

International responsibility also means preserving our common home. The risks of global warming have no borders. Americans and Europeans need to get serious about substantially reducing greenhouse gas emissions in the coming years or we will hand over a much-diminished world to our grandchildren. We need to reinvigorate the US-European partnership on climate change where we have so many common interests at stake. The US and Europe must lead together to encourage the participation of the rest of the world, including most importantly, the developing economic powerhouses of China and India.

I have introduced legislation that would require a reduction in greenhouse gas emissions, but that is just a start. We need a successor to Kyoto, a cap-and-trade system that delivers the necessary environmental impact in an economically responsible manner. New technologies hold great promise. We need to unleash the power and innovation of the marketplace in order to meet our environmental challenges. Right now safe, climate-friendly nuclear energy is a critical way both to improve the quality of our air and to reduce our dependence on foreign energy sources.

That dependence, I am afraid, has become a vulnerability for both the US and Europe and a source of leverage for the oil and gas exporting autocracies. The US needs to wean itself off oil faster. Europe needs a comprehensive energy policy so that Russia's oil and gas monopolies cannot behave as agents of political influence.

The bottom line is that none of us can act as if our only concerns are within our own borders. We cannot define our national interests so narrowly that we fail to see how intimately our fate is bound up with that of the rest of humanity. There is such a thing as good international citizenship. If we wish to be models for others, we must be model citizens ourselves.

Certainly the US must be that model country. Leadership today means something different than it did in the years after the second world war, when Europe and the other democracies were recovering from the devastation of war and the US was the only democratic superpower. Today, there is the powerful collective voice of the EU, India, Japan, Australia, Brazil, South Korea, South Africa, Turkey and Israel, to name just a few of the leading democracies. And there are the struggling young democracies, such as Iraq, Afghanistan and Lebanon, that need and deserve help - more, in fact, than we have been giving. In Russia, democracy has been temporarily suppressed, but we all have an interest in seeing this great nation return to the democratic path soon.

This is not idealism. It is the truest form of realism. It is the democracies of the world that will provide the pillars upon which we can and must build an enduring peace.