Examining data on the recent health care legislation, we demonstrate that public opinion polls on health care should be treated with caution because of item nonresponse — or “don't know” answers — on survey questions. Far from being the great equalizer, opinion polls can actually misrepresent the attitudes of the population. First, we show that respondents with lower levels of socioeconomic resources are systematically more likely to give a “don't know” response when asked their opinion about health care legislation. Second, these same individuals are more likely to back health care reform. The result is an incomplete portrait of public opinion on the issue of health care in the United States.