Economic theory has made considerable progress in explaining why sovereign countries cooperate in trade. Central to most theories of trade cooperation are issues of self-enforcement: The threat of reprisal by an aggrieved party maintains the initial balance of concessions and prevents...

As part of its sanctions regime, the United States recently announced the imposition of punitive import tariffs on 570 product groups from Russia. The European Union may follow suit and enact sanctions on Russia that mirror the US sanctions in scale and scope. Using a sector-specific...