The surprising thing about the case of Dominique Strauss-Kahn and the alleged sexual assault of a hotel chambermaid isn't that all charges have been dropped - it's that he was charged in the first place.
Even if DSK hadn't been one of the world's most powerful, well-known men, the chances of his being found guilty and going to prison were always low, as they are for most men who find themselves accused of rape or sexual assault.
"Rapists who end up being convicted in a court of law must regard themselves as exceptionally unlucky," Professor Joanna Bourke of Birkbeck College argued in her magisterial book Rape: A History from 1860 to the Present.
There is no mystery about this. The hunt for the ideal rape victim is never-ending, but fruitless, for the simple reason that it requires unimpeachable conduct on the part of the victim in every area of her life, past and present.
Women who have been drinking, who know their alleged attacker or who've ever told a lie to a public official, even in an unrelated matter, are not victims prosecutors want to put before juries. What's fascinating about the Strauss-Kahn case - which comes down to the word of the former head of the International Monetary Fund against that of an immigrant from West Africa - is that in the beginning prosecutors clearly believed her story.
So confident was the Manhattan district attorney, Cyrus Vance, that he proceeded to charge Strauss-Kahn, turning him into one of the world's most high-profile defendants.
Even on Monday, when Vance asked a judge to dismiss the charges, he used an ambiguous formulation to explain his change of heart. "The nature and number of the complainant's falsehoods leave us unable to credit her version of events beyond a reasonable doubt, whatever the truth may be about the encounter," he said. This is a classic outcome, signalling not the vindication of the defendant, but the prosecution's judgment that the accuser would not make a good witness.
Vance's own words suggest that his decision was based not on the complainant's account of the alleged assault, but lies she told when she arrived from Guinea and claimed asylum in the US.
If the alleged victim's persuasive account of a violent sexual assault is to be dismissed because she lied to get into the US, the implications for other immigrants are alarming.
This is surely setting the bar too high, as well as sending a message that some potential victims cannot expect the protection of the law. It's well-known that sexual predators often choose their victims with care, selecting girls and women who are 'vulnerable' in some way - black, poor, working-class - and likely to make less-convincing witnesses.
In the case of DSK, fairness demands that his past conduct should also be examined with equally rigorous standards and the picture that's emerged is far from edifying.
French writer Tristane Banon has given a graphic account of what she claims was an attempt by Strauss-Kahn to rape her when she went to interview him in 2003; her mother, Anne Mansouret (a Socialist politician and colleague of Strauss-Kahn) claims that he "took me with the vulgarity of a soldier" during a consensual encounter three years earlier.
It is possible that the former IMF boss is the victim of a truly dreadful coincidence, becoming the victim of slander by women who don't know each other on two continents. But it is also possible he is a sexual predator who targets women who are reluctant to report him, or unlikely to make a good impression on a jury.