MOUNT KISCO, N.Y. — Rep. John Hall (D-N.Y.) may have been a rock star in his former life, but you’d never know it from his public demeanor.

Sure, someone yelled “Hall and Oates?— at him as he trudged down Main Street on a recent muggy Friday — “No, Orleans,— the Congressman was forced to reply, smiling weakly. But Hall is more sweaty than slick, more earnest than apt to talk in sound bites.

And if he had his way, the second-term Congressman would spend as much time as he could working to convince each and every one of his constituents that a Democratic health care reform plan featuring a public insurance option has the most merit.

As he visited with merchants in this economically and ethnically diverse village 30 miles north of New York City — and at the southern end of his Hudson Valley district — Hall spoke at length about the Democratic reform plan and his conviction that it will offer consumers the greatest number of choices and save taxpayers money in the long run.

“It’s kind of like the post office,— he said in Just Dogs, a high-end pet supply shop. “We have a government option for mail. Congress is not going to mandate that you use FedEx or UPS.—

In the air-conditioned cool of the three or four stores Hall had the time to pop into during his 90-minute visit, he found a receptive — if captive — audience, excited to hear him say that health insurance plans for most businesses are unlikely to change.

“I don’t really understand what all the anger is about,— said Leslie Bijoux, proprietor of Yogi’s Paw, a hip clothing boutique, after listening to Hall for several minutes.

But out on the hot streets, it was a different story.

As he walked from store to store, Hall encountered several people along Main Street who seemed almost to appear out of the blue to express their anger — fearful that their health care is going to be taken away from them, worried about a government-run system, and convinced that their children and grandchildren will wind up paying a heavy price in the end.

Most were anything but respectful, considering this was a Member of Congress they were talking to. Hall tried to reason with them, but it didn’t seem to work.

“Are you here to berate my local operation or here to talk health care?— he asked one critic, lawyer Tom Ferrara, who had ambushed him as he started his tour.

“We can’t have a conversation if you’re just going to contradict me and not listen,— he said to a woman, who refused to give her name.

“My biggest fear is the Democrats are going to stay in office,— the woman told reporters after yelling at the Congressman for five minutes.

Watching all the give-and-take as he accompanied Hall down Main Street, Vince Lemma, the president of the Mount Kisco Chamber of Commerce and owner of a real estate insurance business, shook his head.

“And I thought I had a tough job,— he said.

At least some of the heat that’s been generated over health care in the 19th district comes from Hall’s likely 2010 opponent, state Assemblyman Greg Ball (R).

While Hall spent August in a variety of meetings on health care with business leaders, merchants, medical providers and patients, Ball held four very public and very raucous town hall meetings on health care reform across the district.

Just a few hours after Hall’s Main Street walk, Ball held one of his town halls in Cornwall-on-Hudson, a community along the river some 25 miles northwest of Mount Kisco. Despite violent storms, about 200 people packed into a community center — most dead-set against the Democratic health care reform plan and all too happy to express their anger.

As the challenger, Ball said the town halls for him had a dual purpose.

“It gives me the opportunity to be out there, show my accomplishments at the state level,— he said.

But Ball, who has a history of associating himself with controversial and conservative causes, conceded that the meetings were something of a recruiting tool, a chance to meet and then stay in touch with local activists for the duration of the campaign. Ball said he had no idea health care would be such a burning topic this summer.

“I have no control over the national momentum,— he said. “I always said we were going to run a grass-roots campaign that was ready to take back the district regardless of whether there was national support.—

Ball seems to have found a clever way to address — and oppose — health care reform. He uses many of the national Republican talking points, worrying openly about a government takeover of the nation’s health care system, and warning his audience that under President Barack Obama’s push for a public insurance option, patients will no longer have the benefits and choices they now enjoy. To loud applause, he calls for tort reform.

But in a swing district where independents and moderates could have the final word in November 2010, Ball, unlike many national Republicans, is quick to concede that the U.S. health care system is broken and that some national GOP leaders “are intent on making a political statement and making sure that health care reform fails.—

At his town hall in Cornwall, Ball did give his critics a fair amount of speaking time — to the consternation of the health care reform foes, who were clearly out for blood. At one point, someone called a self-identified Democrat in the audience a communist.

If there is a rock star in the Hall-Ball contest, it’s Ball. In contrast to Hall, Ball in public wears crisp suits, his jacket slung over his shoulder just so. At age 31, he is half the incumbent’s age, and he is very quotable. And unlike Hall, a lifelong policy wonk — despite his prior fame — who is passionate about governing, Ball is a pure political animal.

“I guarantee you, Greg Ball is the next Congressman from the 19th district,— said Bill DeProspo, chairman of the Orange County Republican Party in New York, who attended the town hall in Cornwall.

The National Republican Congressional Committee is paying attention. It added Ball to its “On the Radar— list of promising candidates just last week.

But Jonathan Jacobson, DeProspo’s Democratic counterpart in Orange County who also sat in on Ball’s town hall, said Hall will win again because Ball is on the wrong side of the health care debate. He conceded, however, that Democrats are taking Ball seriously.

“We lived through 1994,— Jacobson said.

Sen. Kirsten Gillibrand (D-N.Y.), who knows a thing or two about getting elected in House districts that are traditionally unfriendly to Democrats, said in a recent interview that Hall is doing exactly the right thing on the health care issue.

“I think it’s very productive for all of us to be traveling our states and districts,— she said.

Hall himself is not eager to engage Ball at this point, on health care or any other issue — “a Rose Garden strategy,— by Ball’s own account, “that could be effective.—

“He just got elected to his office last November, and I just got elected,— Hall explained. “I’m working on doing my job. He should be working on doing his job. Next year is the election year. When he’s on the ballot and in the election season, then I’ll talk about him.—