In a campaign that the candidates like to describe as one of the biggest, most consequential ever, perhaps it’s fitting that the biggest, most feathery Muppet in the history of Sesame Street is taking a starring role.

Yes, Big Bird is now on the campaign trail, four weeks out from Election Day. The latest sign: A tongue-in-cheek ad released Tuesday by the Democrats and immediately the target of ridicule by Republicans. Sesame Workshop has asked that the ad be taken down.

It all comes as Mitt Romney has found his footing as a candidate, rising in national polls that show that people now view him more favorably and like him more as a candidate. A new Pew poll has Romney leading President Obama among likely voters 49 percent to 45 percent.

The Big Bird theme started last week, when Romney namedropped Big Bird at the first presidential debate, suggesting that he would cut federal funding for the Public Broadcasting System.

“I’m going to stop the subsidy to PBS. I’m going to stop other things,” Romney said. “I like PBS. I love Big Bird.”

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(One wonders why he didn’t pick Oscar the Grouch, perhaps not as beloved as his neighbor.)

From there, Big Bird was everywhere, a shorthand way for Democrats to express their displeasure at Romney, who bested Obama in the Denver debate according to most viewer polls.

On Twitter, a FiredBigBird account showed up, tweeting its way to 30,000 followers. (Big Bird’s friends, Elmo and Bert later popped up on Twitter, too, lamenting their own downsized fate).

At “Saturday Night Live,” producers tried for Obama and Romney, according to the New York Times, but landed Big Bird instead for a segment on Weekend Update, where he towered over a clearly starstruck Seth Meyers.

During the Virginia Senate debate in Richmond on Monday night, at the local PBS station studio (actual address: 23 Sesame Street), former governor Tim Kaine (D) began his opening statement by saying: “I pledge tonight not to fire Big Bird, and not to defund public broadcasting if I go to the U.S. Senate.”

On Monday, in Derry, N.H., House Speaker John Boehner (R), stumping for Romney, had to share the spotlight with a Big Bird (not the real one), flown in to campaign for Obama.

“The president is making investments in things that matter, while Mitt Romney is giving tax breaks to the wealthiest Americans on the backs of senior citizens, on the backs of the middle class and on the backs of people like Big Bird,” said Holly Shulman, the faux Big Bird’s handler for the day.

Nobody knows what the bird’s politics are (he is only 6), but he has become a kind of joke-surrogate for Democrats looking to belittle Romney as a candidate who sees Big Bird and his friends as a drag on the budget. The Corporation for Public Broadcasting gets about $445 million in federal support over two years.

In the Democrats’ new ad, the 8-foot-tall bird towers over Wall Street, the biggest baddest, meanest of them all. “Big, yellow, a menace to our economy. Mitt Romney knows it’s not Wall Street you have to worry about. It’s Sesame Street,” the ad says. “Mitt Romney. Taking on our enemies, no matter where they nest.”

In response, the Romney campaign sent out an e-mail called “The Clear Choice: Big Ideas vs. Big Bird.”

“Today, the Obama campaign showed us that rather than talk about the issues or offer a serious plan to help the millions of struggling Americans, they’d rather talk about Big Bird,” said Amanda Henneberg, Romney campaign spokeswoman.

“The choice in this election is becoming more clear each day. Four years ago, President Obama said that if you don’t have a record to run on, ‘you make a big election about small things.’ With 23 million people struggling for work, incomes falling, and gas prices soaring, Americans deserve more from their president.”

Republicans were happy to point out the contrast of Democrats talking Big Bird and Romney speaking about foreign policy at Virginia Military Institute on Monday.

“You have to scratch your head when the president spends the last week talking about saving Big Bird,” said Romney, who was campaigning in Iowa. “I actually think we need to have a president who talks about saving the American people and saving good jobs.”

Reince Priebus, chairman of the Republican National Committee, picking up on the Sesame Street meme, invoked The Campaign Count to compare how many times Obama has mentioned Libya in recent speeches (zero) versus how many times the president has mentioned Elmo (five) and Big Bird (eight).

It’s unclear whether the Democrats’ efforts to invoke Big Bird will actually work or backfire and underscore the sense that the campaign is flailing after Obama’s weak debate performance.

The reviews so far haven’t been great — words like absurd, small ball and desperate smallness have been used to describe the Democrats’ Big Bird tactic.

“It pains me to say this, but Barack Obama’s campaign is throwing Big Bird under the bus,” Democratic commentator Carter Eskew wrote in The Washington Post. He added that the focus on Big Bird is a small part of Obama’s attempt to claw his way back from a poor debate performance.

For its part, the Sesame Street gang clearly wants no part of the new partisan version of Big Bird, even as the Obama campaign launched a “Save Big Bird! Vote Democrat!” fundraising campaign.

In a statement Tuesday, it said, “Sesame Workshop is a nonpartisan, nonprofit organization and we do not endorse candidates or participate in political campaigns. We have approved no campaign ads, and as is our general practice, have requested that the ad be taken down.”

“We have received that request.  We’re reviewing it,” Obama campaign spokesman Jen Psaki said aboard Air Force One. “I will say it doesn’t change the fact that there’s only one candidate in this race who is going to continue to fight for Big Bird and Elmo, and he is riding on this plane.”