DES MOINES, Iowa — Former Obama White House chief of staff turned Chicago Mayor Rahm Emanuel served up political red meat to Iowa Democrats at tonight’s Jefferson-Jackson dinner, tearing into GOP presidential frontrunner Mitt Romney with an arsenal of attacks Democrats hope will secure President Barack Obama a second term.

Emanuel proved he hasn’t lost touch with the take-no-prisoners style of politics that won him the nickname “Rahmbo,” opening fire early at the entire field of potential Obama challengers, several of whom gathered hours earlier for a conservative forum just blocks away.

“I’ve watched a number of them, and I’ve got to be honest, I never thought I’d say this,” said Emanuel, his words dripping with sarcasm, “I’m beginning to miss Sarah Palin’s insights.”

Calling the Republicans a “collection of turkeys,” Emanuel laid into each of the potential nominees.

He ribbed Romney for largely avoiding Iowa, joked Newt Gingrich was spending Thanksgiving with his favorite supporters (“the salespeople at Tiffany“), and kidded that Herman Cain spent the day in a “tutorial on Libya,” alluding to the businessman’s gaffe in an interview with the Milwaukee Journal-Sentinel last week.

“The scary part, his tutor was Rick Perry,” Emanuel said, drawing loud laughter and applause.

But the speech — Emanuel’s debut as a high-profile Obama surrogate for the 2012 campaign — focused almost exclusively on highlighting contrasts between Obama and Romney, who was mentioned by name 15 times in the mayor’s 25 minutes on stage.

In broad strokes, Emanuel painted a picture of the Democratic president he once served alongside as a principled executive and commander-in-chief who kept his word on key campaign promises amidst difficult odds.

Citing the end to war in Iraq, the killing of Osama bin Laden, a landmark health insurance overhaul and continued investments in college loan programs and public education, Emanuel heralded Obama-led “change we believed in.”

“That is the change we worked for. That is the change our president delivered,” Emanuel repeated in refrain.

Then turning to Mitt Romney, the mayor described a man he sees as a calculating businessman-turned-politician, whose shifting positions on abortion, gay rights, gun control, climate change, immigration reform and health care reveal no principled core.

“Mitt Romney says he’s a man of steadiness and consistency,” Emanuel said. “And if that’s true, then I’m a linebacker for the Chicago Bears.”

But the mayor made clear Democrats aren’t only girding to attack Romney on flip-flops.

He blasted the former governor for positions on which he has apparently remained steadfast: opposition to the government-funded bailouts of GM and Chrysler while supporting the 2008 bank rescue, and a belief that the ongoing home mortgage crisis should “run its course and hit the bottom.”

“Nothing reveals more about the character and values of these two individuals than how they dealt with these two crises,” Emanuel said of Obama and Romney. “We know where Mitt Romney stood. The title of his own op-ed, under his signature: ‘Let Detroit Go Bankrupt.’”

“The only thing scarier than what Mitt Romney’s flip-flopped on is the issues where he’s refused to change,” Emanuel said later.

Rounding out his address to the enthusiastic crowd huddled in HyVee Hall in downtown Des Moines, Emanuel gave a rousing call to action, clearly aiming to energize Iowa Democrats as then-Sen. Obama did from a similar stage exactly four years ago.

“Can we afford Mitt Romney’s character?”

“No!” the crowd yelled.

“So here’s the deal. You know and I know, our president is a man of character. He’s a man of principle. He’s a man who has been fighting for the middle class and he will continue to fight for middle class families. I know the president’s values. I’ve seen his persistence,” he said.

“You need not ask whether President Obama will continue to fight. … The only question is: Will we fight for his belief in America? So I wanna hear it? Will you fight for the president who’s fighting to save the middle class?”

UPDATE:  Romney spokeswoman Andrea Saul responded to the Emanuel speech in an email to ABC News on Sunday morning.

“The last thing the White House wants is to run against Mitt Romney – which explains their obsessive focus on him and deployment of all of President Obama’s cronies to attack him. President Obama has failed to create a single net new job and has wreaked more havoc on the middle class than any president in modern history. The only job he cares about is his own. So, instead of working to create jobs for Americans, he’s working to create distractions.”