The impulse to do wrong can be irrational and come from a deep and inexplicable place in the psyche
The sociologist Laurie Essig asks in her Chronicle of Higher Education blog:
Why would anyone destroy his career and perhaps even some of those around him for sexual pleasures that did not even involve actual sex? Why would Weiner engage in such pleasures even though he knew there was a right-wing group on Twitter watching every move he made and every young woman he befriended? That is a far deeper and more psychological question, and one that sociology cannot even begin to answer.
One historical answer might be that behind the drive needed to overcome political obstacles -- which many rational people just would not undertake in the first place -- may be the capacity to disregard possible consequences, or even to take pleasure in risk. Larry Craig was surely aware that airport restrooms were especially likely to be patrolled by undercover detectives. There are telling parallels to both Anthony Weiner and Bill Clinton in the 19th-century Prime Minister William Gladstone's mania for erotic literature and rehabilitation missions to prostitutes. As his biographer H.G.C. Matthews put it (via the Victorian Web):
Catherine Gladstone was well informed about these activities, and prostitutes were, almost from the start, invited to the Gladstones' house. But it is also clear that for Gladstone rescue work became not merely a duty but a craving; it was an exposure to sexual stimulation which Gladstone felt he must both undergo and overcome. As he admitted to himself, he deliberately 'courted evil'.
Anthony Weiner has flagellated himself openly but only verbally; Gladstone believed in the real thing, secretly:
In 1849 Gladstone began to scourge himself to counter stimulation from [pornography]. By 1851 he was also scourging himself after conversations with prostitutes during which he felt he had allowed himself to be excessively excited. Sometimes he went to their homes or lodging houses for talks long into the night, sometimes for tea. On occasion he was moved to almost lyrical praise of their beauty, noted in Italian. So far as we know, and there is no evidence to the contrary, he managed to remain, in the end, self-controlled and self-critical.
Yet Matthews also leaves some doubt, and cites an assurance by Gladstone that prefigures Bill Clinton's legally crafted denials almost 150 years later in Monicagate:
[Because of Victorian conventions it] is impossible to know the exact nature of Gladstone's relationship with the prostitutes he visited. The language is guarded but occasionally suggestive. In 1896, seventeen months before he died, he assured his son and pastor, Stephen, that he had never "been guilty of the act which is known as that of infidelity to the marriage bed"; he specifically limited himself "to this negation" a precise and obviously qualified declaration.
The French historian Roland Mousnier raised academic eyebrows in the late 1960s by accepting 17th-century explanations of rebellions and revolutions as the products of original sin. Weiner's Jewish faith rejects that concept -- which the Roman Catholic apologist G.K. Chesterton called the only empirically verifiable tenet of Christianity -- but it has a related one of its own, the evil impulse (Yetzer Hara). A major study of the concept's early history is due this fall.
So in the Weiner affair, maybe the sociologists, psychologists, and historians should also listen to the theologians.