Leading article: The humility that offers hope

He is the new Kennedy, the new Roosevelt, even the new Lincoln. Like Kennedy, he is "an idealist without illusion"; like Roosevelt he offers a New Deal; like Lincoln he wants to make good on the founding principle of the Union that everyone is created equal.

At the same time, he is none of the above. He is the Outsider, an insurgent candidate like no other, who promises a kind of leadership never seen before. His newness goes beyond his race: he embodies change by his age, his upbringing (on the edge of America in Hawaii; outside America in Indonesia) and even his temperament. He will be the first 21st-century president.

For all our understanding that he is a pragmatist, and that the powers even of the US presidency are limited, we can recognise this week as a hinge of history. For all that we know that the new president cannot live up to expectations, despite our ComRes poll suggesting that most Britons believe that he can, we know that something fundamental is changing.

Tuesday marks the End of an Error. An error bravely identified by David Miliband, the Foreign Secretary, just five days before the main author of the mistake ceased to be the most powerful person in the world. The phrase "war on terror" had some merit, Mr Miliband wrote. As well he might; it was Tony Blair, his former boss, who said on 16 September 2001: "The fact is we are at war with terrorism; it is a war between the civilised world and fanaticism." But Mr Miliband now wishes to adjust the dial on the rhetoric machine. "Ultimately," he said, "the notion is misleading and mistaken."

Oh, and – fancy that – here comes a president who understood from the start that the idea of a war on an abstract noun was counterproductive. More than that, one who made the right judgement about the invasion of Iraq.

Of course, George Bush, George Cheney and Donald Rumsfeld were idealists, too. They had a dream, of American power projected around the world in the cause of bringing democracy and prosperity to all. But their judgement was clouded by illusions. They thought that rebuilding Iraq would be a cakewalk and had no idea how this projection of American power would be seen around the world.

This week, we have an American president who suffers no such defects. Whose defining characteristic, as John Rentoul writes today, is a reflectiveness in sharp contrast to the brittle certainties of the Bush administration. "The only thing I know for certain is that these are bad people," said President Bush of the Guantanamo detainees. One of the few things that we know for certain of his successor is that he does not see the world in such binary terms, and will end the abrogation of the principle of freedom at Guantanamo.

It is this humility that offers hope. Hope that it will become more difficult for jihadists to misrepresent the motives of America and its allies as they withdraw from Iraq and engage more intelligently in Afghanistan. And hope in Gaza and the West Bank, which have been so starved of it for so long.

The timing of the Israeli military action in Gaza is, of course, no more coincidental than the timing of Mr Miliband's article about the war on terror. Israel's leaders know that the world is changing on Tuesday. Not that the new president will end the US policy of strong support for Israel. But he changes the intellectual architecture of that support. Which is important because the Israeli-Palestinian issue can be solved. For years, the problem has been one of sequence. The main terms of a settlement are known and indeed have been agreed by both sides, but at different times.

At some point, Israel's leaders have to be brought back to the words of Chaim Weizmann, their nation's first president, who said in 1947: "I am certain that the world will judge the Jewish state by what it will do with the Arabs." Compassion is not simply a moral imperative, it is a pragmatic policy that will yield greater security for all in the long run. If anyone can persuade the Israelis, and the Americans and the rest of the world of this, it is the man who enters the White House this week.

Not that Tuesday is a moment of biblical deliverance, in the Middle East or anywhere else. It is, as the President-elect said yesterday, "just the beginning" of a journey. Yet when he said, "Let's seek a better world in our time", it meant a little more than the usual windy rhetoric of the newly elected politician. Nobody expects him to transform everything, but we really can hope that a new US president, of good heart and cool head, will summon us to make the world a better place. In our time.