CHICAGO – President Obama summed up his closing arguments for the 2010 midterm election at a get-out-the-vote event here Saturday that was bigger than any election rally ever held in this city. Nearly 50,000 people massed in Hyde Park, just blocks from the president’s Chicago home, to hear him warn that returning power to Republicans would embolden corporations and the wealthy with disastrous results for working and middle-class Americans.

James Price, 58, an electrician from nearby Hammond, Ind., said that he’s been at “countless rallies ever since I lost six good friends to the war in Vietnam. This is the first time I felt that I had a personal duty to be at a rally and that I have a moral obligation to vote because the very existence of our democracy is at stake. The tea party scares me. But what scares me more is the big money and the big corporations behind them.”

Sally Kaminski, a librarian who lives on the city’s North Side, emerged from a Metra train into which she had been packed, with hundreds of other rally-goers, like a sardine in a can.

“I’m not crazy about the people running here in Illinois,” she said. “But I support the president, I believe in the change we fought for in 2008 and I’ll be damned if I let the corporations or the monsters who call themselves Republicans destroy this country.”

Price and Kaminski walked down the long staircases onto 57th Street where crowds coming off buses coming up from the South Side and down from the North Side moved slowly through the streets toward the giant rally.

“Chicago, I need you to keep on fighting. Illinois, I need you to keep on believing. I need you to knock on some doors. I need you to talk to your neighbors,” Obama told the cheering crowd of tens of thousands.

The spirited rally happened while last minute campaign activities by labor and its allies were at a fever’s pitch.

From Friday morning until noon Monday, union members across the country made 5 million phone calls, knocked on 4 million doors and passed out 1.5 million flyers, surpassing what they have done in all previous election campaigns.

AFL-CIO leaders are predicting that the result will be a “firewall” on Nov. 2 that protects Democratic majorities in both the House and the Senate.

Regardless of what happens it is clear that momentum shifted to Democrats in many races across the country this weekend with tea party candidates losing ground in Alaska, Colorado, West Virginia and , according to some polls, Kentucky. In Ohio the incumbent Democratic governor, Ted Strickland, who had been trailing his Republican opponent John Kasich, was closing the gap.

The huge turnout at the Jon Stewart-Stephen Colbert rally in Washington D.C. on Saturday was also seen as a rejection of tea-party right-wing extremism.

Republicans made their closing arguments over the weekend by saying, basically, that President Obama and “big government” were responsible for the economic crisis. While the GOP expects to take over the House and hopes to win control of the Senate, Democrats and many progressives expect the pundits will be surprised.

The New York Times’ Nate Silver, who has been predicting a huge Republican victory, backed off those predictions Oct. 31. “This is a really strange election, or at least one that pollsters are having an awfully difficult time getting a handle on. Claiming you can predict Republican gains within a range of 5 or 10 seats isn’t science – it’s superstition.”

Almost all the experts say the youth vote will be critical. If all the young people who voted the first time in 2008 came out again, they note, no Republican takeover of Congress would be remotely possible.

OurFuture.org quoted Jed Lewison who had “four questions for undecided voters.”

First was what the average monthly private sector job growth was in 2008, the final year of the Bush presidency and what it has been so far in 2010. Second was what the federal deficit was for the last fiscal year of the Bush presidency and what it has been so far in 2010. Third was what the stock market was on the last day of the Bush presidency and what it is now. His fourth question was, “Which party’s candidate for speaker is campaigning this weekend with a Nazi re-enactor who dressed up in an SS uniform?”

Paul Krugman, the Nobel prize-winning economist, expressed concern this weekend that GOP “moralizing about debt” could lead some voters to vote for economic pain.

“More and more voters,” Krugman said, “are convinced that what we need is not more stimulus but more punishment. Governments must tighten their belts; debtors must pay what they owe. The irony is that in their determination to punish the undeserving, voters are punishing themselves: by rejecting fiscal stimulus and debt relief, they’re perpetuating high unemployment.”

Photo: President Obama and cheering supporters at a Moving America Forward rally for Democratic candidates, Oct. 30 in Chicago. Charles Rex Arbogast/AP