At what point does a preposterous film become preposterous? In Consenting Adults, is it when Kevin Spacey drives his motorcycle out of the moving van and into his garage, demonstrating to his new neighbors just what a wild card he is? Is it when the film's husbands agree to swap wives secretly in the middle of the night, believing the women will be too sleepy to recognize they're having intercourse with an impostor? (Which, one might add, removes a bit of the "consent" from the title). Or does the total descent into idiocy wait until the final showdown, in which Spacey inexplicably brandishes an Uzi submachine gun as "self defense"? However it's sliced, Alan J. Pakula's Consenting Adults, a thriller about dysfunctional marriages, is pretty dysfunctional itself. The best thing going for it is that it starts out at least resembling the structure of other thrillers, approaching plausibility now and again. But its central portion -- sometime after this ill-fated nighttime switcheroo -- is rife with red herrings, leaps in logic, and shoddy camerawork. If the viewer can't determine who's in on the scam and who isn't, that should be because the narrative establishes an air of mystery about the characters -- not because the execution is incompetent. Even if Consenting Adults wasn't fatally flawed as a production, its essential gender politics should give a thinking person pause, as the film's women are grossly mishandled by their men. That's fine if that's the filmmaker's message, but the weakness of the female characters seems more a careless accident than a device intended to expose male ugliness.