Christopher Wlezien has an article at The Journal of Politics titled "News and Public Opinion: Which Comes First?" Abstract:
Much research demonstrates a positive association between news coverage and public opinion, both perceptions and preferences. While this relationship is clear, what accounts for it is not. The assumption in most previous research is that media causes public opinion. But there is reason to expect that the causality runs in the other direction as well. In this article, I describe the logic of two-way flows and then undertake an analysis of three different cases of US public opinion over time—economic perceptions, candidate support, and policy preferences—using measures of the content of news coverage based on automated content analyses. Vector autoregression results indicate that opinion “causes” coverage in every case, and the reverse holds less frequently and always to a lesser degree. The results underscore the role the public can play in news coverage, one that always should be entertained and assessed empirically, not settled by assumption.