The Chamber of Commerce is leading the opposition to the health care bill with a coalition called Employers for a Healthy Economy. In two weeks, the group has bought more than $7 million in television advertising and plans to spend up to $3 million more. Americans for Prosperity, a group financed by David Koch, the oilman, is also jumping into the fray with an advertising campaign of nearly $1 million.

For weeks, Democrats who support the health care legislation have struggled to compete with the opposition. A disparity in radio and television advertisements, along with calls and mailings, meant that the lawmakers Mr. Obama and Speaker Nancy Pelosi were trying to persuade to vote for the measure were taking a pounding in their districts.

The new money from Pharma, the association of drug makers, as well as contributions from labor unions and other groups helped equalize the advertising fight. This week, officials said, the groups backing the legislation will focus extensively on the insurance industry with this theme: “When insurance companies win, you lose.”

The strategies for the climactic week ahead go well beyond vote counting in the corridors of the Capitol. Until this week, a divided Democratic Party struggled to raise money to compete with forces rallying against the measure, so creative approaches were used.

Television advertisements were cost-prohibitive in the district of Representative John Adler of New Jersey, who voted against the health care bill last year, so proponents formed a special grass-roots action campaign. A dozen members of the clergy who support overhauling the health care system recently met with the congressman’s rabbi, who said he would talk to Mr. Adler about the legislation.

Mr. Obama is making daily telephone calls to Democrats who supported the health care bill last year, but have yet to decide how they intend to vote this time. He is also focusing on those who opposed the legislation, including Representative Dennis J. Kucinich of Ohio, who said the measure did not go far enough.

The president’s trip to Ohio includes Mr. Kucinich’s district, and he invited the congressman to join him aboard Air Force One. Mr. Kucinich said he was grateful for the ride and for the president’s visit, but added that he was disinclined to support the bill as it stands.