President Barack Obama vowed he would "never stop fighting" for struggling Americans, in a fiery political counter-attack meant to mend Democratic morale and his frayed bond with voters.

Obama sought to recapture the passion of his 2008 campaign, after a wake-up call from voters in liberal Massachusetts who sent a Republican to the Senate, and with his health care plan and wider agenda under assault in Congress.

"I'll never stop fighting to give every American a fair shake," Obama said at a town-hall style meeting in the rust-belt state of Ohio, a vital bellwether in mid-term elections in November shaping up as another hit for Democrats.

Striking populist notes, Obama said he would fight Wall Street to restore home values, for his embattled health plan, to stop credit card companies cheating customers and to cut "exploding" deficits.

Five days before his showpiece State of the Union speech, Obama also showed no sign of backing down on reforming health care, even as the historic bill looks to be becalmed in Congress.

"I got to admit, we hit a bit of a buzz saw," Obama said of the year-long effort to pass the reform, which now looks doubtful after Democrats lost their 60-seat Senate supermajority needed to thwart Republican blocking tactics.

"I had no illusions when I took on health care. It was always going to be hard," Obama said.

"And I'm going to keep up the fight for real, meaningful health insurance reforms."

Posing as the champion of regular people, Obama added: "I can promise you, there will be more fights in the days ahead."

Obama critics, some of them Democrats, have faulted him for not being sufficiently passionate in fighting economic blight, for siding too much with Wall Street and appearing aloof while everyday Americans struggle.

But with his soaring approval ratings of just a year ago wilting, the president told a crowd in Ohio: "You know what, I win when you win."

"So long as I have the privilege of serving as your president, I'll never stop fighting for you. I'll take my lumps, too."

His day of rubbing shoulders with Ohioans in colleges, factories and a small town bar were designed to enhance the president's "regular guy" credentials and to convince people he knows how tough things are.

"The truth is, being president is also a little confining," Obama said, explaining how he came to neglect his connection with Americans as he faced multiple crises in his first year in office.

"I can't just walk around and visit people like I used to. I can't just go to the barber shop or sit at a diner."

Obama noted the political tumult following the loss by Democrats of a seat in Massachusetts ? which deprived his party of the Senate supermajority it needed to pass major legislation unchallenged by Republicans.

While lashing out against the financial industry, Obama also justified his highly unpopular decision to stick with the previous administration's bank bailout plans.

Had he not acted, he said, the country would have fallen into a second Great Depression, which would have taken a terrible future toll on ordinary Americans, or Main Street.

In the depressed town of Elyria, Obama made a surprise stop at a bar and restaurant known as "Smitty's ? Where Friends Meet," in an apparent bid to burnish his image as a man of the people.

He bumped into one man, 98-year-old Charles Raynor, who was just about to tuck into a plate of French fries.

"I am just pleased to see Charlie is still eating fries at 98," Obama said as he posed for a picture.

Another man, Shawn Hatcher, was sitting at the bar celebrating his 42nd birthday.

"Nothing wrong with 42. I am 48," the president said, adding, "I am going to buy this guy's lunch."

Republicans boosted by this week's victory of insurgent candidate Scott Brown in Massachusetts are cranking up their own populist rhetoric.

"For the past year, Ohioans have watched anxiously as Washington Democrats, with the approval of President Obama, have pushed a job-killing agenda that includes a 'stimulus' that isn't working," said John Boehner, the top Republican in the House of Representatives who represents an Ohio district.

Unemployment in Ohio is 10.6 percent, even higher than the brutal national average of 10 percent.

But the White House says Obama's 787-billion-dollar economic stimulus plan has created 79 000 jobs in the state.