Winning Our Future, an outside group backing Newt Gingrich for president, is up with a new ad in Iowa pushing back against those in the "Republican establishment" seeking to derail his campaign.

"The Republican establishment wants to pick our candidate," says the ad's narrator. "When a principled conservative took the lead they outspent Newt Gingrich 20 to 1, attacking him with falsehoods."

The ad then promotes Gingrich's conservative bona fides.

The group has promised to spend $1 million before the Jan. 3 Iowa caucuses, with much of it focused on the Hawkeye State. That lags behind the outside groups backing Mitt Romney and Rick Perry, both of which have already spent more than $2.5 million on ads in the state. This is the first major salvo of the promised ad buy, and has more than a quarter of a million dollars behind it.

Gingrich has been the target of millions of dollars of negative ads, many of them from the pro-Romney group Resture Our Future. This ad does not attack Romney by name, as Gingrich has asked his supporters not to attack the other candidates, but strongly suggests who they're talking about.

"Don't let the liberal Republican establishment pick our candidate," the ad closes.

Watch it here: