The battle over reforming the U.S. health care system has intensified in recent weeks, and the political stakes are growing for President Barack Obama as well as for Democrats and Republicans in Congress.

Grass roots democracy can be chaotic at times, and members of Congress are getting a first-hand glimpse of the anger and fear that is dominating many of their town hall forums across the country to discuss health care.

"This is not health reform, this is control! Control over our lives!" shouted one man at a recent meeting in Iowa. But raucous crowds are showing up at town halls all across the country.

Pennsylvania Senator Arlen Specter, a Democrat, had his hands full trying to calm down a man in Lebanon, Pennsylvania, who was angry about being denied a chance to ask a question.

SPECTER: "Now wait a minute. Now wait a minute! Wait a minute. You want to leave?"

MAN: "Well, I got news for you. You and your cronies in the government do this kind of stuff all the time. One day God is going to stand before you and he is going to judge you and the rest of your damn cronies up on the [Capitol] Hill, and then you will get your just desserts!"

Passions are running high because reforming the U.S. health care system is an enormous undertaking that affects virtually all Americans, and because many of the proposals are politically polarizing.

President Obama and his Democratic allies in Congress want to expand health-insurance coverage to 46 million Americans who currently do not have it. In addition, the administration wants to bring down the soaring cost of health care for consumers, businesses and the government.

In an attempt to regain political momentum in the health-care debate, Mr. Obama told a town hall in New Hampshire that Republicans are hoping to kill the reform effort this year like they did in 1993 and 1994 under former President Bill Clinton.

"Every time we come close to passing health insurance reform, the special interests fight back with everything they have got. They use their influence and their political allies to scare and mislead the American people. They start running ads. This is what they always do. We cannot let them do it again. Not this time. Not now," he said,

Republicans oppose the Obama health care approach as too costly and warn the administration plan could affect the quality of care for those who already have health insurance coverage.

"We would like to make a deal, but we would like to make the right kind of deal. I mean, this is not about embarrassing anybody politically. This is about getting it right. This is one-sixth of our economy. Health care is an enormous issue. It affects every single one of us and we want to get it right," said Senator Mitch McConnell of Kentucky, who leads Republicans in the U.S. Senate. He appeared on Fox News Sunday.

Polls show public support for Mr. Obama's push for health-care reform has weakened in recent weeks, and the constant drumbeat of criticism at the town hall meetings has fed the perception that the political momentum for reform has slowed.

"Republicans have been able to get some traction with this idea that the government is expanding in all kinds of ways that are going to have unintended consequences and unforeseen effects on your lives," said Matt Dallek, a political expert at the Bipartisan Policy Center in Washington.

Democrats say some of the town hall displays are organized disruptions encouraged by Republicans and conservative groups intent on demonizing government involvement in health care.

They take issue with opponents, some of whom invoke images of Nazi Germany and accuse the Obama administration of wanting to trample the Constitution and individual rights.

Some liberal groups that support the Obama plan are starting to fight back, fearful that reform critics have effectively slowed down the efforts of the White House and congressional Democrats.

"There are people in the country who want to stop an honest, fair, civil and moral conversation about health care. They are organized and they really want to shut down democracy, and we can not let that happen," said the Reverend Jim Wallis, president of Sojourners, a Christian group that supports progressive causes.

Political analyst John Fortier of the American Enterprise Institute believes the critics of the reform effort will continue to batter the Obama plan throughout August when members of Congress are on recess and hosting town-hall meetings.

Fortier says that might force Democratic congressional leaders to pull back a bit on their reform plans when they come back to work next month.

"I think there is still a reasonable chance they could pass something, but they are going to have to come back, I think, and regroup in September and we may see that things are a little bit different than they are today, even perhaps a little more precarious for the passage of health care in September," he said.

President Obama and congressional Democrats want a health-care package approved before next year's midterm congressional elections. Republicans believe that blocking the Obama effort could help their political fortunes in next year's election and in the 2012 presidential election as well.