Matt Yglesias makes a good point in this post about adultery in US politics: solidarity is probably the #1 indicator of whether a negative “nanostory” (in the catchy lingo from a certain awesome new book)
survives or not. If you can’t get enough people on the miscreant’s “side” to attack them, then you can’t successfully run them out of town. The media start to doubt themselves. Most to the point, the story can’t properly build—all the attackers will start attacking immediately, so that the volume cannot be turned any higher, because the copartisans hold firm.

This is one reason why legal investigations tend to be the counterexample to this rule: when there’s a drip, drip, drip of new evidence, then you can keep the story building even if the copartisans refuse to crack.  And then, usually, they do crack, because even the talk-radio guys can’t stay on board in that scenario.

So, the moral of the story for smearers (or spreaders of accurate dirt): drip, drip, drip.

(Related.)