Parties are spending millions on advertising for the health bill passed by the Obama administration. The add campaigns are targeting the 40 House Democrats whose votes who will determine the fate of President Obama’s top domestic priority.

An alliance group supporting the health care plan made $12 million investment for the final advertising push. The Chamber of Commerce is leading the opposition of the health bill. The coalition called Employers for a Healthy Economy spent $7 million in TV advertising and is planning to spend $3 million more.

Democrats who support the health care bill have struggled to compete with the opposition.