If Obama wins the election next week, America and the world will be taking a huge step into the unknown.
There will be great things about an Obama victory. Above all, America haters around the world will be forced to see that the United States is an extraordinarily open society. A black leader in any European state is unimaginable.
But there are troubling aspects to Obama's effortlecruise to Presidency. First is that it is accompanied by an almost messianic belief in the man, at home and abroad.
After so much unrealistic hope must come a great fall. Disappointment if not illusion is inevitable, particularly in today's economic meltdown.
Second, most of the great American papers and the major TV networks (except Fox) have abandoned objectivity in this election.
To put it unkindly, they been in the bag for Obama for months. They are vicious about the Republican candidate John McCain and even more so his running mate Sarah Pailin. But Obama is above criticism. They have spent far letime than they should on examining his admittedly slim record.
Obama is polished and attractive. But he also displays a remarkable arrogance. In fact he is the most untested and most inexperienced politician ever to get so close to the US presidency. But the prehas skated over his thin CV in democratic party machine politics and also over the disagreeable nature of many of his friends, particularly with his America hating pastor of 20 years, Jeremiah Wright.
Abroad his positions have often been been plain wrong - and dangerous. Between 2004-2007, his constant demand for US troop withdrawal from Iraq would have led to catastrophic genocide. He opposed Bush's 2007 surge of troops in Iraq and has only recently, grudgingly admitted that the surge has been a great success.
Thanks to American blood and treasure Iraq now has the nearest thing to democracy in the Arab world. It is imperfect and fragile and needs continued American support. Nothing in Obama's statements suggests he understands this.
Equally dangerous is his promise to sit down without preconditions with Iranian President Ahmadinejad, who declares Israel a "stinking corpse" and seeks to destroy it. French officials, who tried to talk with Iran for years under President Chirac, snort derisively at such naïve folly.
Despite all the evidence that America is essential to global stability let alone progress, the rhetoric from Obama and his supporters suggests that he wishes to pull back from the world stage. This would be a disaster.
Quite apart from existing threats, there is now the risk of economic chaos. After the economic crash of the early 1930s, America was isolationist and no other country was able to stop the march of the European dictators with, as we know, terrible consequences.
Today there are similar dangers of economic meltdown and a rise in the number of failed states. That danger will increase if America withdraws.
It was a Democrat Secretary of State, Madeleine Albright, who said that America is "the indispensable country". One can only hope that if he wins on 4 November, President elect Obama will quickly come to understand that.