In an interdependent world the risks faced by any one agent depend not only on its choices but also on those of all others. Expectations about others' choices will influence investments in risk-management, and the outcome can be sub-optimal investment all round. We model this as the Nash...

This paper characterizes the efficient sequential equilibrium when a government uses indirect control to exert its authority. We develop a dynamic principal-agent model in which a principal (a government) delegates the prevention of a disturbance--such as riots, protests, terrorism, crime, or...

A notable feature of post-World War II civil wars is their very long average duration. We provide a theory of the persistence of civil wars. The civilian government can successfully defeat rebellious factions only by creating a relatively strong army. In weakly-institutionalized polities this...

Do firms have adequate incentives to invest in anti-terrorism mechanisms? This paper develops a framework for addressing this issue when the security choices by one agent affect the risks faced by others. We utilize the airline security problem to illustrate how the incentive by one airline to...

This paper discusses how an industrialized country could defend the wages and social benefits of its unskilled workers against wage competition from immigrants. It shows that fixing social standards harms the workers and that fixing social replacement incomes implies migration into unemployment....

Migration of young workers (as distinct from retirees), even when driven in by the generosity of the welfare state, slows down the trend of increasing dependency ratio. But, even though low-skill migration improves the dependency ratio, it nevertheless burdens the welfare state. Recent studies...

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...

We study a reform that granted European cross-border workers free access to the Swiss labor market and had a stronger effect on regions close to the border. The greater availability of cross-border workers increased foreign employment substantially. Although many cross-border workers were highly...

We develop a political-economy model of economic union and compare the competion regime to the coordination regime. Key policy differences emerge between the two regimes: concerning the generosity of the welfare state and the skill composition of migration. We argue that the differences between...

We study the effects of labor mobility within a currency union suffering from nominal rigidities. When the demand shortfall in depressed region is mostly internal, migration may not help regional macroeconomic adjustment. When external demand is also at the root of the problem, migration out of...