President Obama’s political allies launched a tough new campaign Wednesday against Mitt Romney, previewing a harsh line of attack the Democrats may drive should he become the Republican presidential nominee.

The “Mitt Romney’s America” campaign includes a new Web site and video alleging that Romney is a protector of Wall Street who, if elected, would isolate Main Street and decimate the middle class.

The group behind the campaign, Priorities USA Action, a so-called super PAC created by former Obama White House aides, says it is spending about $100,000 to run advertisements on Google, YouTube, Facebook and other social media outlets.

The video is set to a fast-paced, harrowing soundtrack and has the feel of a Hollywood movie trailer for a scary thriller. It splices a black-and-white photo of a young Romney holding dollar bills with his suited-up Bain Capital partners with images of a corporate jet and an unemployment line.

And it features footage of Romney on the campaign trail, both this year and during his 2008 campaign, to create a sort of blooper reel that includes his oft-repeated quips that “corporations are people” and “there are a lot of reasons not to elect me.”

The video closes with a quick succession of words in red boldface: unregulated, isolated, decimated, relocated, privatized, dismantled, slashed and repealed. Then, the climax: “Mitt Romney’s America is not our America.”

But the narrative the group is pushing contrasts with the tone Romney has been trying to set on the campaign trail. The former Massachusetts governor has been pitching himself as an advocate for the middle class, highlighting at recent town hall meetings his plan to eliminate taxes on savings interest, dividends and capital gains for those making $200,000 a year and less.

“I’m running for middle-class Americans,” Romney said Oct. 10 at a townhall meeting in Milford, N.H. “I want to help the people who’ve been hurt by the Obama economy, the people in the Where’s Waldo economy.”

The next day, at the Washington Post-Bloomberg debate at Dartmouth College, Romney said: “I want to focus on where the people are hurting the most, and that’s the middle class. I’m not worried about rich people. They are doing just fine. The very poor have a safety net, they’re taken care of. But the people in the middle, the hard-working Americans, are the people who need a break, and that is why I focused my tax cut right there.”

The video campaign leaves little doubt as to who the Democrats believe will face Obama in next year’s general election. It comes amid a more intensified Democratic assault on Romney. Top Obama advisers David Axelrod and David Plouffe recently attacked Romney in television interviews for his inconsistencies on issues over the years, while the Democratic National Committee has been pummeling him almost daily through and other avenues.

“As Americans look ahead to a critically important election a year from this week, we are beginning the process of helping Americans know the truth about what Mitt Romney’s America would look like,” Bill Burton, a senior strategist for Priorities USA Action, said in a statement.

In a statement responding to the Priorities USA Action campaign, Romney spokeswoman Andrea Saul said: “While Mitt Romney is focused on his jobs and economic plan which will provide relief for the middle-income taxpayers, President Obama and his cronies are worried about their own jobs. It is no surprise since President Obama cannot run on his failed record that his political allies resort to false and negative attacks on Mitt Romney.”