Democratic presidential candidate Hillary Rodham Clinton is proposing billions of dollars a year Wednesday to keep jobs from being shipped abroad as she appealed to blue collar workers in Pennsylvania, the next big primary contest where she hopes to trim rival Barack Obama's lead.

Obama seemed to ignore the former first lady, turning his political guns on presumptive Republican nominee John McCain to blast his stands on the Iraq war and the economy.

Clinton has come under pressure from Obama supporters in recent days to drop out of the contest because of what some see as the Illinois senator's insurmountable delegate lead with just 10 primaries and caucuses to go.

But the former first lady showed no signs of quitting as she focused on job creation and challenges to the U.S. economy at campaign appearances across Pennsylvania, which holds the next primary contest on April 22 with 158 delegates at stake.

At an economic summit in Pittsburgh on Wednesday organized by her presidential campaign, Clinton was expected to propose the elimination of tax breaks for companies that move jobs to other countries and use the savings to provide $7 billion a year in tax incentives to persuade companies to "insource" jobs in the United States

Pennsylvania and other states holding upcoming primaries, including Indiana and Kentucky, have suffered the loss of manufacturing jobs in recent years and have yet to transition to new industries and other ways of expanding their economies.

Clinton's plan would offer new tax benefits for research and job development. It would also create "innovation and research clusters" and provide $500 million annually in investments to encourage the creation of high-wage jobs in clean energy.

Obama tried to look past his nomination battle with Clinton to the general election matchup with the Republican nominee-in-waiting John McCain, who has been playing up his foreign policy and national security experience.

The Associated Press has learned that Obama is picking up the endorsement of former Indiana Rep. Lee Hamilton, the top Democrat on the panel that investigated the Sept. 11 attacks, which could boost his national security standing.

Hamilton planned to announce the endorsement Wednesday. He is the highest profile Indiana Democrat to back Obama before the state's May 6 primary.

The former Indiana lawmaker served on the House Foreign Affairs Committee during his more than three decades in Congress and also was co-chairman of the Iraq Study Group, a bipartisan commission that assessed U.S. policy in Iraq.

On Tuesday, Clinton lashed both the Republicans and Obama, most notably with vows not to quit the race and likened herself to a hometown Philadelphia legend, the film boxer Rocky Balboa.

"Let me tell you something, when it comes to finishing a fight, Rocky and I have a lot in common. I never quit. I never give up. And neither do the American people," Clinton said Tuesday at the Pennsylvania AFL-CIO convention in Philadelphia. The organization is one of America's largest labor union federations.

The Pennsylvania vote, in which polls show Clinton with a comfortable lead over Obama, is key to the former first lady's bid to whittle down her opponent's overall lead in popular votes, delegates and states won.

According to the Associated Press tally of delegates, Obama leads Clinton 1,632-1,500, including the so-called superdelegates, elected officials and party leaders who can vote for whichever candidate they want regardless of primary and caucus outcomes. A total of 2,024 delegates are needed to win the nomination at the party's national convention this summer in Denver.

But Obama turned his attention to McCain as if victory in the increasingly bitter nomination race against Clinton were a foregone conclusion.

"He's on a biography tour right now," Obama said of McCain. "Most of us know his biography, and it's worthy of our admiration. My argument with John McCain is not with his biography, it's with his policies."

McCain has opened a drive in recent days to define himself as a candidate with an impeccable military pedigree and experience in national security issues absent in either Clinton or Obama.

For his part, Obama has argued that a McCain victory would be another four years of President George W. Bush on economic and military policies.

"Senator McCain has been saying I don't understand national security, but he's the one who wants to keep tens of thousands of United States troops in Iraq for as long as 100 years," Obama said.

McCain has said the U.S. could end up having a long-term military presence in Iraq, similar to the more than 50-year presence of U.S. soldiers in Germany and South Korea.

"One hundred years in a country that had nothing to do with 9/11 may make sense to George Bush and John McCain but it is the wrong thing to do," Obama said, drawing applause at the town-hall session.

McCain spokesman Tucker Bounds said Obama's remarks showed his "complete lack of preparedness to be commander in chief."

"His attempt to paint McCain's position as something else is nothing but the disingenuous, old-style politics that he claims to reject," Bounds said.

Clinton assaulted McCain as a candidate who would stand back and watch as the U.S. economy spiraled downward and blamed Bush for the nation's deepening financial difficulties. She announced support for a plan to create 3 million new jobs to rebuild the U.S. infrastructure.

Obama latched onto the same theme, promising to create jobs by using $60 billion he said would be saved by ending the Iraq war.