For a country often criticized for its lack of political participation, Americans have been remarkably active, taking over public spaces from New York to Los Angeles to protest excessive corporate profits, petitioning to stop bullying against gays and to promote environmental causes, and signaling that issues from heart health to disaster relief are important to them.  Market activism, which seeks change by or through industry, is not new.  From the Boston Tea Party to Civil Rights’ “Don’t Buy Where You Can’t Work” campaigns, consumer tactics were designed to make change to government, through government, or in places where government had refused to take action.  However, what distinguishes market activism today from market activism of the past are any of these governmental ties.  If corporations and nonprofits are providing another non-political venue to address social issues, what are the political implications?  Does market activism erode political participation, augment political participation, or provide a new opportunity not connected to political participation?   To answer these questions, I examine the most common form of market activism, cause marketing, where a portion of the purchase price of consumer goods goes to support a social or political cause.  Through a national survey of 1500 Americans and in-depth case study of breast cancer activism, I show that in contrast to political activism, market activism defines problems narrowly with easily solutions that are easy to accomplish.  It creates new market-based institutions that, in turn, define and depoliticize social issues.  The long-term effect of market activism is to create a powerful social understanding of problems around which political and non-political institutions form and take action.