The first lesson of international relations is that democracies don't go to war with on another. In his 1994 State of the Union addresss, President Clinton said that no two democracies have ever warred with each other. The conventional wisdom is that world peace can be achieved through universal democracy.

Unfortunately, this is not quite true. There are important exceptions. And exceptions probe, never prove, rules. The exception that makes even established democracies take up arms against one another is fish.

Consider recent history: Diplomatic relations between Canada and the U.S., uniquely amicable, are nowhere more antagonistic than over fisheries policy. Canada has fired upon New Englanders allegedly poaching scallops. At the end of 1992, twenty Scottish trawlers blockaded one of their own harbors to prevent French supertrawlers from using the port. A few months later, German and Danish fishermen went on strike and Scottish fishermen spilled oil on Russian catches. Meanwhile in France riotous fishermen confronted the British Royal Navy, French riot police, and blockaded ports. Last year, Spain dispatched armed naval vessels to fisheries off Canada's coast as part of an ongoing dispute which included the seizure of Spanish vessels on the high seas by Canadian gunboats. For decades Brits, Norweigans, and Icelanders have exchanged shots in naval skirmishes as part of their "cod wars". More recently, violence between Spain and Portugal has escalated from knives and axes to naval gunfire.

And it gets worse elsewhere: A Falklands naval vessel chased Taiwanese fishermen all the way across the Atlantic Ocean. Russia has sent warships to the high seas to "protect" them from foreigners, like the Japanese. Earlier this year, the "pacific" island nation of Kiribati (population 79,000) arrested and detained a Puyallup man and his vessel at machine-gunpoint.

Could the stakes be so high that fish bring violence and conflict to otherwise peaceful relations? Hardly, if you consider that fishing accounts for less than 1% of the GDP in most of Europe and the U.S.

This instability doesn't bode well for the post-Cold War peace. If we can't manage the diplomacy of fish, how can we manage nukes, human rights, or terrorism? Moreover, the problems keep mounting. The number of fishermen has doubled since 1970, while their catch has been falling steadily since 1989. This means more over-capitalized fishermen fighting over the last scraps of dwindling fisheries.

Why do democracies fight over fish? An incomplete legal system provides no clear way to settle conflicts. Fisheries can fall under national jurisdiction, no jurisdiction, and sometimes both. As fish and fishermen cross borders, laws change and cheating becomes an artform. In the European Union, for example, illegal catches amount to half the legitimate total.

Secondly, fisheries heritage promotes tension, misbehaving, and conflict. National politics coddle fishermen, giving them privileges akin to those of farmers. Protections include cash subsidies, free access to public fisheries, and navies eager to punish foreigners for fishing improprieties. Worldwide, governments spend an estimated $54 billion in subsidies to harvest just $70 billion in fish. This means the net value of the world's fisheries is only $16 billion -- Phillip Morris had triple that in sales last year, the cosmetics industry ten times that.

With subsidies and open access, too many fishermen chase too few fish. In that scramble for the last profitable fish, people cross others' lines and capture others' livelihoods. Then mature democracies roughhouse.

Why the fighting? Marine ecology makes everyone interdependent. International fisheries are commons, subject to the predictable "tragic" outcomes when coordinated management and limitations are absent. When countries share fisheries and any nation overfishes, the others suffer. The international community has struggled to devise institutional arrangements capable of effectively managing their fisheries commons. Bitter conflicts naturally result.

Within nations, special interests distort public policy. Fishermen in these democracies mobilize support from a sympathetic public and politicians support the industry with a war of escalating subsidies. The results are nations worse off for wealth transfers, a fishing industry tragically overinvested, and a depleting resource.

How could we stop the fighting? Rules must recognize complexities of fisheries. When fish cross political borders, ecology trumps sovereignty. Management must give participants a secure stake in the future of their fishery. Only then will their decisions integrate the biological and the economic factors into a conservation strategy.

Resolution of the problems would come quicker if fishermen knew they must fend for themselves, no subsidies or bailouts. The key problem is the temptation of politicians to champion the cause of the noble fisherman at the expense of taxpayers, healthy industries, and sustainable fisheries. This exemplifies the special interest problem so pervasive in democracies worldwide.

Exceptions probe the rule. With fish, we see conflict because the international system of sovereign states is ill-suited to resolve commons problems, and national politicians have incentives to benefit their special interest fisherman. These factors lead to violent conflict. We explore these issues further in our forthcoming book from Indiana University Press, Managing the Commons.