As Marianne Gingrich airs her grievances, Newt Gingrich smiles and waves to his growing crowd of supporters in South Carolina. Like a parade announcer with his mistress of ceremonies beside him, he mocks Barack Obama to the laughs and claps of the sidewalk watchers. He criticizes the critics and implies by his refusal to be daunted by his own past that, just for today, his Palmetto State spectators should revel with him in temporary glory!

His buoyancy appeals; his buoyancy also appalls. For all his compelling ideas, for all his impressive experience, for all his adverbial eloquence, nothing in his campaign suggests that he alone is the candidate to conquer the menace that is Barack Obama. Nothing suggests that he alone can effectively articulate conservative principles. But much in his campaign suggests he thinks he alone is the candidate who should prevail.

On the one hand, that is the nature of a campaign; No one nominates himself for president unless he is convinced that he would be best for the job. On the other hand, Gingrich seems possessed of that conviction more so than any of the other candidates. Indeed, he has always seemed to think he was destined for greatness. With just one year of full-time teaching experience under his belt, for example, Gingrich applied to be college president. A year later, he applied again for a post above his station — to be the chair of the history department. On the political stage, he proved his ambition again and again — often to good effect for the conservative cause. The Contract with America. The Republican Revolution. Are any catch-phrases associated with Gingrich not connotative of grand gestures and great accomplishments? Now, we learn — if we can take Marianne Gingrich at her word — that he clung to Callista in part because she “was going to help him become president.” No, Gingrich has never lacked ambition.

Since his last period of prominence, though, Gingrich has been converted in ways he discusses freely. Much of the evidence of his campaign runs contrary to the idea that Gingrich is still prey to any avarice for power — and suggests instead that he is aware of his own weak tendencies and wants to systematically combat them. The campaign policies he initially implemented — especially the pointed civility to his fellow candidates — seemed aimed to ensure he’d remember that he wasn’t seeking power for himself, but rather that he was seeking power for the Republican Party. As long as he was civil to his fellow candidates, it would be easier for him to convince himself that he cared only that the GOP triumph, not necessarily that he triumph.

Who could ever forget the sincere testimony he delivered at the Thanksgiving Family Forum? For weeks, I was enamored of him because I thought he really understood what so few politicians seem to understand: That the power of the presidency is on loan from the people, that the presidency is a repository of power, but not the source of its own power. It’s evident by what he said at that event that he was very genuinely grappling with that idea and seeking to internalize it. By that grappling, I am still impressed.

It appears, though, that it’s true: Something in the very fact of wanting power seems to disqualify folks from possessing it. For it wasn’t long before Gingrich’s ambition reasserted itself. He began to attack his fellow candidates; he implied his rivals should drop out of the race; and, now, he brushes aside the bitterness of his ex-wife.

When I first read Marianne Gingrich’s attacks upon Gingrich this morning, I was neither shocked nor angry. I was just sad — sad for her and sad for him that his increasingly successful presidential bid brought out a kind of pettiness and vindictiveness in her. Like Ed, I questioned her timing and her insensitivity to Gingrich supporters and the rest of his family. But, gradually, the news reawakened my wariness of Gingrich. No doubt he has accomplished as much for the conservative cause as any contemporary, but he has sacrificed personal integrity along the way.

Beneath the flowery floats and the overinflated balloons, beneath a new theme and new decorations, the Gingrich parade is still driven by the same vehicle — the same old unbridled ambition, ambition that seems to think the ends justify the means.