Slate's Dickerson claimed both Democrats and Republicans are using deceptive push-polling, but provided only GOP example

In an October 30 article documenting Republican "push-polling," in which political campaigns make phone calls purporting to conduct surveys but in fact push a particular viewpoint and often smear an adversary, Slate.com chief political correspondent John Dickerson baselessly suggested that Democrats are "no doubt using the same tactics but haven't been caught doing it as flagrantly yet." In his article, Dickerson provided no examples or reports of Democrats using push-polling, while providing the transcript and audio link for an automated push-poll phone call on behalf of Tennessee Republican Senate candidate Bob Corker. As Media Matters for America has documented, ABC News and NBC News have similarly suggested that both Democrats and Republicans have engaged in "mudslinging" and "dirty tricks," respectively, while providing only Republican examples of such behavior.

From Dickerson's October 30 Slate article:

Help, I've been push polled and I can't get up! During this final week before Election Day, the usual hue and cry has been raised about automated phone calls interrupting the dinner hour. The robotic voices ask questions as if they're conducting a genuine political survey but then deliver talking points favorable to the Republican candidate. (Democrats are no doubt using the same tactics but haven't been caught doing it as flagrantly yet.)

[...]

My bet is that the push polls are as effective as hurling fistfuls of leaflets from your car window. We'll see after Election Day whether the races targeted with these appeals show an increase in Republican turnout, and whether these techniques contributed to that. But early signs are that indiscriminate calling is firing up Republican opponents.

—R.M.