WASHINGTON -- The health care battle bubbling over in town-hall-style forums across the nation this month is shifting to TV screens as groups on each side of the issue launch multimillion-dollar ad blitzes to influence the debate.

Advocacy groups such as the U.S. Chamber of Commerce and the AARP are spending a combined $500,000 on health care ads every day, according to the non-partisan Campaign Media Analysis Group, and are reaching TV viewers in more than 20 states.

The bombardment of advertising comes as President Obama and Democrats in Congress have tried to refocus the national dialogue about health care and explain their proposals after some lawmakers faced stiff criticism at town-hall-style meetings at home this month.

"We've gone from a situation where everyone is cheerleading on the sidelines to where everyone is putting on the pads and getting on the field," said Evan Tracey of the Campaign Media Analysis Group. "You're really starting to see this stuff pop."

All groups have invested a combined $57 million in health care ads this year, Tracey said. Overhaul supporters have outspent opponents roughly 2-to-1.

A coalition called Americans for Stable Quality Care launched a $12 million campaign Thursday supporting the health care effort. The ad, focused on how the legislation would affect people who have insurance, highlights a provision that protects people with pre-existing conditions from losing coverage.

"It's going to be a very noisy August," said Ken Johnson of the Pharmaceutical Research and Manufacturers of America, the drug industry's trade group and a leading funder of the new coalition. "We're trying to raise awareness of why health care reform is so important."

The ads will initially run for two weeks in 12 states, including Maine, Colorado, Virginia and Montana, said Ron Pollack, executive director of Families USA, another member of the coalition. The states are home to lawmakers who could be swing votes on health care.

"We want to provide support to key members of Congress so that when they vote for health care reform, their constituents understand why," Pollack said.

Earlier in the week, the Chamber of Commerce began airing a spot that criticizes legislation proposed by Democrats that would create a government-run insurance program, saying it would lead to an expensive and inefficient system. The ads are running in 21 states, including many represented by moderates.

R. Bruce Josten, the chamber's top lobbyist, cited reports that supporters of government-run insurance may spend millions on ads this month. "We need to create a dialogue rather than allow those groups to have a monologue," he said.

Obama will add to the discussion with two town-hall meetings: one in Montana today and one in Colorado on Saturday. Senior White House adviser David Axelrod, meanwhile, sent a chain e-mail to supporters criticizing what he called "lies and distortions" from some against the legislation, urging them to pass his message along to others.

Congress was expected to vote on health care legislation before leaving Washington for the August recess but delayed action until September to give members of the Senate Finance Committee more time to develop a bipartisan bill. Many lawmakers have faced angry voters at meetings in their districts.

Richard Kirsch of Health Care for America Now said his coalition of unions and non-profits had planned to run advertisements this month long before the protesters made news, "but the climate puts our message into sharper relief."