Greg Sargent reports [emphasis added]:

I'm told by a CNN source that the network privately pressed cable operators not to run the Media Matters ad attacking Dobbs, which pilloried his footsie with the birthers as CNN's “Lou Dobbs problem.”

Media Matters had previously booked a week's worth of ad time on MSNBC, Fox, and CNN — during Dobbs' show.

The pressure, which came before CNN publicly acknowledged that they were nixing the ad, suggests that the network may have been more rattled by the campaign against Dobbs — and by the prospect of public criticism of Dobbs running on the network — than has been previously known. The network may have hoped to shut down the ad without being publicly associated with that effort.

It's also rather intriguing that CNN has been unwilling to pressure Dobbs to rein in the birther talk — but was willing to press cable operators not to run a paid-for ad questioning it.

Why on earth is CNN urging competing cable news outlets not to run specific ads? Bizarre.