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A coalition of conservative groups and Republican lawmakers led by freshman Wisconsin Rep. Sean Duffy is celebrating the second anniversary of the passage of President Obama's $814 billion stimulus bill on Thursday by trying to defund what's left of it.

But with Democrats still in control of the Senate and the White House, getting federal money back after it’s been obligated may not be as easy as conservative activists wish.

Duffy, a former MTV reality star, was elected to fill the seat of longtime Democratic Rep. David Obey, the author of the stimulus bill who retired instead of facing what was expected to have been a tough re-election battle. Duffy introduced legislation last Thursday to return the $168 billion unspent portions of the stimulus back to the Treasury. Another $7 billion in uncommitted funds remains unspent.

"What's become clear to Wisconsinites and Americans is that the so-called 'stimulus' has failed," Duffy said in a written statement, noting that the unemployment rate has remained at 9 percent or above for 21 consecutive months despite the administration's sales pitch that the stimulus would prevent the rate from rising above 8 percent.

"Rescinding the remaining stimulus funds and sending it back to the Treasury for deficit reduction would send an important message to the private sector that there has been a fundamental shift in the People's House from pushing big government policies to pro-growth policies that will empower the private sector to innovate and invest," he said.

Sen. Jerry Moran, R-Kan., introduced a companion bill in the Senate on Thursday.

The second anniversary of the stimulus arrives on the same week that Obama released his $3.7 trillion budget for 2012 that top Republicans have dismissed as "unserious." Republicans are seeking deep budget cuts while Obama wants to invest in the future.

Conservative groups organized by Let Freedom Ring launched a new website last week that includes a petition in support of Duffy's bill and offers sharp criticism of the stimulus package.

Colin Hanna, president of Let Freedom Ring, told FoxNews.com that the coalition formed quickly in recent weeks as several of them began discussing ways to commemorate the second anniversary of the "failed" stimulus plan.

"We said instead of focusing on the plan that has failed to achieve its objective and therefore the anniversary is a regrettable reminder of that, we ought to do something more active, to see if the unspent dollars can be defunded."

The other groups in the coalition are Americans for Tax Reform and Restore the Dream Foundation.

George Behan, a spokesman for Washington Rep. Norm Dicks, the top Democrat on the Appropriations Committee, told FoxNews.com that Duffy's proposal would derail the economic recovery.

"It's undeniable that the stimulus created jobs. It's undeniable that we're in a fragile part of the economic recovery," he said, arguing that Duffy's legislation would kill jobs by rescinding money committed to road projects where people have already been hired. "The unemployment rate is still high. Increasing unemployment will only worsen the problem."

Behan said he's confident that Duffy's proposal will not get past the Senate or the White House.

"Ultimately, it's not going to become law," he said.

But Hanna remains hopeful since the proposal has been attached to a must-pass temporary spending bill that will prevent a government shutdown.

"I wouldn't be surprised, since it's a must-pass legislation, to see it survive," he said.