How does the interplay of geography and political-economic forces affect the shape of nations? This paper presents a quantitative framework for characterizing the equilibrium evolution of national boundaries in a world with a rich geography. The framework delivers simple equilibrium conditions...

International economic integration yields large potential welfare effects, even in a static constant returns competitive world economy. Our method is novel. The effect of border barriers on trade flows is often inferred from gravity models. But their rather atheoretic structure precludes welfare...

The gravity model has been widely used to infer substantial trade flow effects of institutions such as customs unions and exchange rate mechanisms. McCallum [1995] found that the US-Canada border led to trade between provinces that is a factor 22 (2,200%) times trade between states and...

The paper first extends and reconciles recent estimates of the strikingly large effect of national borders on trade patterns. Estimates comparing trade among Canadian provinces with that between Canadian provinces and U.S. states show interprovincial trade in 1988-90 to have been more than...

The paper first assesses regional and ethnic group differences in social trust and memberships in both Canada and the United States. The ethnic categories people choose to describe themselves are as important as regional differences, but much less important than education, in explaining...

Extending McCallum's (1995) result, based on a gravity model of 1988 trade flows, that a typical Canadian province trades 22 times more with other provinces than with U.S. states of similar size and distance, this paper asks how Quebec trade patterns compare with those of other provinces. The...

What are the economic impacts of a border wall between the United States and Mexico? We use detailed data on bilateral ows of primarily unauthorized Mexican workers to the United States to estimate how a substantial expansion of the border wall between the United States and Mexico from 2007 to...

This paper investigates the link between violent crime and immigration using data from Colombian municipalities during the recent episode of immigration from Venezuela. The key finding is that, following the closing and then re-opening of the border in 2016, which precipitated a massive...

Are country borders still an impediment to trade flows within Europe? Using a rich microlevel survey with 3 million annual shipments of goods by road across 269 European regions, we construct a matrix of bilateral trade flows for 12 industries from 2011 to 2017. We then use the causal inference...

This paper argues that redrawing subnational political boundaries can transform ethnic divisions. We use a natural policy experiment in Indonesia to show how the effects of ethnic diversity on conflict depend on the political units within which groups are organized. Redistricting along group...