Once in a great while, a cable news anchor overcomes the flaws of the medium, turns in a stellar performance, and permits facts to prevail over spin. For disaffected viewers like myself, these surprising moments are worth savoring like a pleasant conversation with an airplane seatmate or a tasty supermarket tomato. My favorite example will probably always be Chris Matthews doggedly refusing to let Kevin James off the hook for not knowing what the hell he was talking about, because the offending blowhard was shamed in exactly the way his entire cohort deserves.

At the other end of the spectrum: Lawrence Donnell's execrable interview with Herman Cain.  

Newt Gingrich is beyond shame. But in the clip above, Anderson Cooper does something that is very difficult on television. Without ever interrupting the former House speaker, Tiffany & Company patron, and highly remunerated Freddie Mac historian, he determinedly pressed him to concede what is in fact true: that one campaign advertisement criticizing President Obama has factual errors -- or as Gingrich finally put it, that there is no evidence for an assertion that it makes.

Never mind the advertisement.

What I realized, after watching the clip, is how sleazy so many of these cable news appearances by Republican and Democratic politicians and hangers on are. Every week, people like Gingrich go on TV, endeavor to make eye-contact through the camera, and marshal a disreputable skill they've long honed: extemporaneous speaking that obscures truths inconvenient to their allies and misleads the audience, even when they stop short of the most brazen lies.

Look how expert Gingrich is at it! 

Our political parties mint these people. News organizations keep putting them on the air, which ought to be scandalous in itself. Typically what follows are monologues each of which could inspire new categories of transgressions in an updated version of Politics and the English Language. At best, the surrogate does his best to obscure reality, only to be defeated by Anderson Cooper, one of the good ones. But if that's the best possible outcome why have Newt Gingrich or his Democratic analog on at all? Why not just banish partisan hacks from your network?

There is a journalistic obligation to counter spin, but not to air it in the first place.