This research tests if political discussion influences policy preference. The literature greatly stresses the non-rational nature of political decision-making. Rational policy preferences require learning specific details in a competitive political environment. Yet, research shows that most people do not have the skills to understand policy. Social networking is one way to help people understand policy. Social network influence on policy preferences, however, is mostly ignored. We show that the likelihood of supporting a policy increases when one's social network supports a party that advocates that policy. We control for the political knowledge of the respondent, network size, partisanship, ideology, socioeconomic, and policy-specific determinants. Examining data from the 2000 American National Election Study and Japanese Election Study 3, we find strong results in the United States, but mixed results in Japan. Additional research we perform shows a stronger social network influence in Japan.