Something big has happened in America. Even before the primaries season has really got going, the candidates have been whittled down to three. On the Republican side, John McCain goes into Super Tuesday in a commanding position. His only serious Republican rival, Mitt Romney, is trailing badly in opinion polls in all the big states that vote this week.
On the Democratic side, Hillary Clinton and Barack Obama go into Tuesday's primaries and caucuses in 22 states as the only remaining credible candidates. In contrast to the Republican contest, which seemed wide open 31 days ago but now seems almost over, Senator Clinton's early lead has been eroded. If Senator Obama gains more from the withdrawal of John Edwards, he could even win the biggest prize on Tuesday, California. Even if he fails, the proportional system used by the Democratic Party to allocate delegates to the national convention means that he could stay in the race.
The crucial point, though, is that the election in November of any of the three remaining candidates, Senators McCain, Clinton and Obama, would mark an abrupt break with the politics of the Bush years. This is a shift of some magnitude and a hopeful opportunity for the US and the world. Plainly, if a Democrat took the White House, things would change – and not just because the US would have its first female or African-American president. Clinton and Obama both disagree profoundly with Bush's world view.
This we know. What may be less well appreciated is that McCain does, too. He is a different kind of Republican. Nor is this simply a veneer of "compassionate conservatism" of the sort adopted by President Bush. The prospect of a McCain candidacy has drivencore conservatives in the US to despair. CommentatorAnn Coulter, admittedly one of its more shrill exponents, said last week that if McCain were the candidate, she would campaign for Clinton.
It is, therefore, worth subjecting McCain's record to some scrutiny. As Geoffrey Lean, our environment editor, writes today, he probably has the best green credentials of the three candidates. He has proposed bills in Congress to cap US emissions of greenhouse gases. Unlike many Republicans, he is opposed to drilling in Alaska.
But it is not just his green policies that should make him attractive to centre-ground voters in the US and commend him to the sensible centre of world opinion. He opposed the President's tax cuts because they favoured the wealthiest. He is opposed to the legal Wonderland of Guantanamo Bay and wants to close it down. He is categorical in his opposition to torture, and says that waterboarding (a technique that makes victims think they are drowning) is torture. And he says this with the authority of one who was tortured by the North Vietnamese during his six-year stay in a Hanoi prison camp.
The main reasons for alleging that he would be no improvement on President Bush are his support for the invasion of Iraq and for the surge. But those are two separate things: one is history; the other is not necessarily wrong. It was possible for humanitarians and progressives to support the invasion – as Clinton did – but that is no longer the issue. The question is what to do now and, although the evidence that the surge is "working" has been oversold by supporters of the war, it could well be argued that maintaining high US troop levels in northern Iraq is less disastrous than pulling out quickly.
Finally, McCain has shown some political courage. He fought the primary in Michigan, the car-making state, saying that "those jobs will not come back". Michigan gave him its answer, voting for Romney, but it was McCain who prevailed.
Thus the choice Americans will make in November is likely to be between a liberal, green Republican and a liberal, green Democrat. Of course, there are limits to what can be achieved, even by the most powerful elected politician in the world. And, of course, in European terms, all three remaining candidates would be classified as right of centre – although that distinction is not what it was. This newspaper was among the first to give David Cameron some credit as a socially liberal, green Conservative. The point is that any of the three would be very different from President Bush.
Eight years ago, as the new millennium dawned, there was much talk of a new world order. That optimism was crushed by 9/11, President Bush's response to it, and the tragedy of Iraq. But now optimism, of a more cautious and realistic kind, seems justified. There is hope of action against climate change; hope for the rule of international law; hope for global social justice.
Whoever wins the US election in November, the world will shift on its geopolitical axis.
To have your say on this or any other issue visit www.independent.co.uk/IoSblogsReuse content