Perhaps the most telling critique of Obama, to my mind, is his lack of executive experience. (The same can be said for Clinton, of course, if you don't count the First Lady period, when she insists her husband was the president.)  I asked him directly last year why a voter should back someone who has never run anything bigger than a legislative office. He responded by pointing to his nascent campaign. He observed out that he was up against the full Clinton establishment, all the chits she and her husband had acquired over the years, and the apparatus they had constructed within the party. He had to build a national campaign from scratch, raise money, staff an extremely complex electoral map, and make key decisions on spending and travel. He asked me to judge his executive skills by observing how he was managing a campaign.

By that standard, who isn't impressed? A first term senator - a black urban liberal - raised more money, and continues to raise much more money, than Senator Clinton. More to the point, the money he has raised has not come from the well-connected fat-cats who do things like donate to the Clinton library. His base is much wider, broader and internet-based than hers. It has many more small donors.

Now look at the strategy he laid out last year, as he explained it to me and others. Iowa was the key. If he didn't win Iowa, it was over. But if he could win Iowa, he would prove the principle that a black man could transcend the racial issue, helping in New Hampshire, and then also helping him peel off what was then majority black support for the Clintons in South Carolina. Then his strategy was meticulous organization - and you saw that in Iowa, as well as yesterday's caucus states. Everything he told me has been followed through. And the attention to detail - from the Alaska caucus to the Nevada cooks - has been striking.

Now consider the psychological and emotional challenges of this campaign. It has been brutal. It has included many highly emotional moments - and occasions when racism and sexism and all sorts of hot-button issues have emerged. Then there was the extraordinary spectacle of a former president and spouse bringing the full weight of the Democratic establishment and the full prestige of two terms in the White House to dismiss some of Obama's arguments as a "fairy tale" and frame him as another Jesse Jackson.

How did the candidates deal with this? The vastly more experienced and nerves-of-steel Clinton clearly went through some wild mood-swings. Obama gave an appearance at least of preternatural coolness under fire, a steady message that others came to mimic, and a level of oratory that still stuns this longtime debater. In the middle of this very hot zone, he exhibit a coolness and steeliness that is a mark of presidential timber. He played tough - but he didn't play nasty. Keeping the high road in a contest like this - without ever playing the race card or the victim card - is an achievement. Building a movement on top of that is more impressive still. So far, he has combined Romney's money with Clinton's organizational skills and Ron Paul's grass-roots enthusiasm. No other campaign has brought so many dimensions into play.

And he won Missouri.

(Photo: Obama at the Apollo by Hiroko Masuike/Getty.)