Geography, international trade, and political mobilization in US industries

From studies of "Silicon Valley effects" to regional economic development, the spatial proximity of firms is shedding new light on some of the most enduring puzzles in business and economics. Yet few studies examine whether spatial proximity leads individuals with shared interests to be more politically active. We address this question by examining whether geographic concentration makes individuals in industries exposed to international trade (i.e., through export orientation or import competition) more likely to mobilize politically. Studying U.S. manufacturers in 1998 and 1990, we find that, for trade-exposed industries, geographic concentration strongly increases (a) the formation of common trade policy preferences among workers; (b) employees' contributions to political campaigns; and (c) voter turnout. This activism traces not to the behavior of political elites, but rather to the increased possibility for collective action that spatial proximity affords individuals in trade-exposed industries.