International law solves a laundry list of existential risks.

These attacks on international law are sometimes dismissed as isolated events, disconnected acts of animus toward specific treaties or institutions. Nothing could be further from the truth. Behind these individual attacks lies a comprehensive vision of the rule of law in world affairs, one that treats international law not as a means of achieving American objectives but as an unnecessary and unjustified limitation on the exercise of American power. Consider the following statement from a 2005 Pentagon National Defense Strategy: “Our strength as a nation state will continue to be challenged by those who employ a strategy of the weak using international fora, judicial processes, and terrorism.” International law in this view is not simply a worthless diversion. It is a real and serious threat to US national interests. Those who hold this extreme view have successfully guided foreign policy to break with the country’s long history of using international law to achieve American values and interests.

As the 2008 election looms, it is time to challenge this dangerous vision and reaffirm and rebuild America’s historical commitment to international law. No longer can critics of the Bush Administration merely show where it has gone wrong. They need to articulate a vision of international law and its place in US foreign policy that is grounded in our common interests and values. In laying out this vision, the point to emphasize is not that a renewed commitment to international law will help us win back the respect of the rest of the world (though it will) or even that the United States, as the most powerful country in the world, has a special responsibility to support international legal institutions (though it does). Rather, the case for international law as a cornerstone of American foreign policy should begin with a more basic message: only through a robust engagement with international law can the United States promote its national interests in the modern, globalized world.

In an interdependent world, international law is frequently the simplest, most effective and least expensive solution to problems big and small. Let us start with the many small ways the law improves our daily lives. It might be possible to fly an airplane from New York to Paris without the benefit of international law. But it would take a lot longer and would be a lot more cumbersome and expensive–requiring carefully chosen routes, long waits for overflight permissions and uncertain reception upon arrival. Likewise, it might be possible to send a letter from one part of the world to another or buy a piece of clothing from another country without the benefit of international law, but it would almost certainly be more difficult and cost a great deal more than it does today. Indeed, much of international law is indispensable for coordinating and regulating commerce, transport, communication and other hallmarks of global interchange. Without these basic ground rules, our dynamic global system would slow to a crawl.

Engaging with these basic international legal regimes is essential, but alone it is not enough to maintain America’s place as a robust, modern world power. The greatest benefits of international law come from institutions that ask more of us and hence give more in return. The World Trade Organization, for example, ensures low-cost access for US exports to markets in much of the world. Yet we cannot take advantage of this access without giving access in return. And we cannot get others to follow the rules of fair play in the marketplace unless we are willing to do so ourselves.

But international law does more than establish the ground rules or level the playing field of international commerce. It also can help us solve many of the thorniest problems we face. Put simply, global problems require global solutions. There are many problems we cannot solve ourselves, no matter how powerful our nation or how committed our leaders. The most obvious example is global warming. Every country emits greenhouse gases, and every country will ultimately feel the effects of global warming. Yet no country can combat the problem alone. Even if the United States, which is one of the two biggest greenhouse-gas emitters, were to cut its emissions in half tomorrow, global warming would continue. That’s because the United States is only part of the problem–and hence can produce only part of the solution on its own.

A less obvious example is terrorism. No state can effectively fight terrorism in isolation. Terrorist organizations evade national control by sending their money, people and weapons across state borders. Only by working together can states effectively combat this transnational threat. There are budding efforts to do just that at the United Nations–spearheaded by the United States. In the weeks immediately following 9/11, the Security Council adopted Resolution 1373 requiring states to take measures to prevent and suppress the financing of terrorists by criminalizing terrorist funding, freezing terrorist assets, suppressing recruitment of terrorist agents and prosecuting accused terrorists. Resolution 1373 and follow-up resolutions have proven to be some of our most effective tools in combating terrorism.