CORNWALL-ON-HUDSON, N.Y. — An intense thunderstorm swept through the Hudson Valley late Friday afternoon, felling trees, knocking out power and providing some relief from the stifling summer heat.

But it did nothing to lessen the intensity of the debate over health care reform in the 19th district, where Rep. John Hall (D) and his likely Republican challenger, state Assemblyman Greg Ball — along with their supporters — have been skirmishing over the issue all month.

Shortly after Friday’s storm, 200 people packed a community center in this riverfront town, the site of significant Revolutionary War battles, for Ball’s third town hall this week on health care. Earlier in the day, across the Hudson and to the south, Hall discussed reform proposals with merchants in the ethnically and economically diverse Westchester County village of Mt. Kisco.

Both encountered critics along the way — though the challenger presided over a far more raucous event.

“People are so activated right now,— Ball said.

That was an understatement. People began streaming into the room an hour before the town hall’s scheduled kick-off, and several people carried signs criticizing the health care reform proposals being circulated by Democratic leaders in Washington, D.C.

One night earlier, Ball and his supporters ambushed Hall at a health care meeting the Congressman co-sponsored with a local chapter of the NAACP in Beacon. After initially being banned from the event, Ball and company forced their way into the meeting, but Ball was denied the opportunity to speak, even though several of his allies did get to ask questions and make comments.

“I know there are some plants and some Democratic operatives in the room, but I’m not scared of you,— he boasted.

True to his word, though, 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. Someone else insisted that the reform bill advancing in the House “was written by outspoken advocates of euthanasia and assisted suicide.—

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.

“You don’t think docs and nurses are going to be on the public payroll in 30 years?— he asked the audience. More than a few times, he joked that he doesn’t “want to have to go to the [Department of Motor Vehicles] for open heart surgery.—

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.—

Even as he took some swings at Hall, Obama and Speaker Nancy Pelosi (D-Calif.), Ball periodically preached civility throughout the town hall, and praised a young critic, saying it was heartening to see “a young man engaged in public discourse, not outside a Starbucks on a skateboard.—

What’s more, Ball said he would take all he learned at his health care forums — a final one is scheduled for next Thursday, and former Rep. Joseph DioGuardi (R-N.Y.), who represented parts of the district in a previous incarnation, will be there — and synthesize them into a dozen recommendations that he would present to Hall with the hope that the Democratic incumbent would include them in reform legislation.

But don’t bet on Hall carrying Ball’s legislative recommendations to Capitol Hill any time soon. The Congressman is a passionate defender of the public option, and he is dismissive of Ball’s efforts to make political capital of his opposition to health care reform. Without mentioning Ball by name, Hall said Friday that his challenger is part of a movement that is being fueled “by an organized e-mail and telephone campaign, Freedom Works, certain candidates, Dick Armey, Newt Gingrich, and talk-show hosts like Rush Limbaugh and Sean Hannity.—

Hall encountered two kinds of people during his walk down Main Street in Mt. Kisco Friday. The business owners he sought out were hopeful to enthusiastic about the Democratic health care plan.

“When we have people apply for jobs, the first question is not what you’re paying, it’s what kind of health insurance are you offering,— Robert Brache, owner of Elephant’s Trunk, seller of women’s custom-made formal wear, told Hall.

But Hall encountered critics along the way — some of whom seemed to appear out of the blue for the express purpose of badgering him.

“We do not want government health care!— yelled one woman who refused to give her name.

“You are by far in the minority, in this district and in the nation,— Hall replied.

“No, we’re not!— the woman fumed.

“We have to agree to disagree,— Hall said, offering his hand, which the woman refused to shake.

After some more conversation, the Congressman told the woman, “You have misconceptions.—

“You have misconceptions!— she yelled.

“I’m the one who’s actually there, in Washington, D.C., participating in caucus meetings and watching the legislation get written,— he went on. “We can’t have a conversation if you’re just going to contradict me and not listen.—

To both supporters and critics, Hall laid out what he sees as the proposals’ advantages in considerable detail. He compared the public option to the nation’s mail delivery system: The post office is a public entity, but Congress is not preventing people from shipping goods via Federal Express and UPS.

“The contents of the different bills are confused and distorted— in the public discussion, he said. “Part of what we’re doing here is explaining what’s going on and answer questions and just listen.—

Watching all the give and take as he accompanied Hall down Main Street, Vince Lemma, the president of the Mt. 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.