Democrat Barack Obama today rejected Hillary Clinton's claims to be a champion of working families and portrayed his presidential rival as a defender of corporate interests and the status quo.
Mr Obama, speaking to a Pennsylvania AFL-CIO convention one day after Ms Clinton appeared before the labor group, said the New York senator was too closely tied to corporate lobbyists to bring real change to Washington.
"I'm the only candidate in this race who's actually worked to take power away from lobbyists by passing historic ethics reforms in Illinois and in the US Senate. And I'm the only candidate who isn't taking a dime from Washington lobbyists," said Mr Obama, an Illinois senator.
He mocked Ms Clinton's recent efforts to compare herself to Rocky Balboa, the underdog boxer featured in the "Rocky" movies.
"We all love Rocky, but Rocky was fiction. And so is the idea that someone can fight for working people and at the same time embrace the broken system in Washington, where corporate lobbyists use their clout to shape laws to their liking," Mr Obama said.
Mr Obama and Ms Clinton are in a hard fight for the Democratic nomination to face Republican John McCain in November's presidential election. They had spent the last few days training their fire on Mr McCain rather than each other.
They both campaigned in Pennsylvania today ahead of the next showdown there on April 22nd. Ms Clinton, in Pittsburgh, announced a proposal to eliminate tax incentives for companies that send jobs to foreign countries and provide $7 billion a year in new tax benefits and investments for companies that create US jobs.
"I believe our government should get out of the business of rewarding companies for shipping jobs overseas, and get back into the business of rewarding companies that create good, high-wage jobs - with good benefits - right here in America," she said.
Polls give Ms Clinton a solid lead in the state three weeks before the vote. A Quinnipiac University poll showed her with a 9-point lead on Mr Obama in Pennsylvania.
Mr Obama picked up the endorsement on Wednesday of Lee Hamilton, a former Indiana congressman and an influential authority on foreign relations. Hamilton co-chaired two blue-ribbon commissions that investigated the September 11 attacks and advised President George W. Bush on the war in Iraq.
His support offers a boost for Mr Obama, who has faced charges from Ms Clinton that he is too inexperienced to be commander in chief.
Mr McCain assailed Mr Obama's foreign policy credentials as well today. "I know he's inexperienced and I know he's got a lack of knowledge" about national security, the Arizona senator said.