The thing about Barack Obama is that he can give a speech. No doubt it is not the only quality he has, but it's enough to justify his claim that he represents change.

Bill Clinton has the same ability. The former president can stand in front of an audience and talk and talk, and the gestures and the voice combine to make you pay attention, even if you disagree with the words. Obama has the same skills as an orator, except that his sentences are more disciplined, more grammatical and in a sense more dramatic.

This is the secret of his appeal. His politics and his proposals are virtually the same as Hillary Clinton's and those of most of the other Democrats who also used to run for the Democratic nomination. But by the power his his words alone, Obama makes these policies sound a lot more reasonable and middle-of-the-road than they sound coming from the others.

The contrast is glaring when Obama's rhetorical style is compared to that of President Bush. People who have time with the president in private insist that he's very good in a conversation, smart, quick and sometimes funny. But little of that comes through when he speaks off the cuff in public, when he often sounds as though he's giving a high school recital and afraid any second of making a mistake.

In any case Bush sounds defensive. It is this that no doubt has contributed to his declining popularity once his substantive policies - from the economy to the war - turned out poorly.

We don't know whether his rhetorical skills could rescue a President Obama from a series of reverses on the policy front. He might well falter under the kind of withering criticism that accompanies the beginning of failure at the top of politics.

But the ability to give voice to ideas is more than just a superficial skill. It is the most important tool a would-be national leader has.

Facing thousands of people in the Portland Memorial Coliseum - really facing them, turning around to look at the people behind him - Obama gave a performance the people who heard and saw it will not soon forget. (hh)