The Russian military buildup along the Ukrainian border and Vladimir Putin's seizure of Crimea have become pivotal moments for Western powers and NATO.
During the Cold War, the Kremlin had little doubt that if the Soviet Union attacked or invaded Europe -- anywhere in Europe -- it would have a full-scale conflict with NATO and the United States. Today, frankly, it's unclear what would happen if Russia seized Moldavia or, say, two cities in eastern Ukraine.
Those who say they long for the clarity and symmetry of the Cold War forget the danger of living under an international regime in which "stabilizing deterrence" was the threat to incinerate half the planet. But a new, volatile period brings dangers and instabilities of its own.
There are enclaves all over this world populated by minorities that, like Crimea, would on balance rather be part of a nation other than the one they find themselves in.
There are parts of the world with natural resources like oil or gas -- such as the South China Sea -- that become natural strategic objectives for surrounding countries. Energy and food will be subjects of strategic contest for many decades to come because not all countries have both, and the haves are tempted to use energy and food as instruments of coercion vs. the have-nots.
There is no international body with the strength, the legitimacy and the freedom to act that can guarantee national integrity for all countries.
The United States and Europe are both in economic difficulty, and both have sought to reduce military spending and commitments. For most of the period since World War II, the western alliances have been both dominant and stabilizing; today they are shrinking and uncertain.
And there are areas of potential international conflict that are not primarily defined by traditional geographic boundaries, such as cyberspace and China's drive to dethrone the dollar as the sole global reserve currency. On the latter, there can be little doubt that the wily Putin is probing not only China on this subject, but also fossil fuel-producing enemies of the West, since the production and sale of oil and gas are significant parts of hard-currency transactions.
Stopping expansionists like Putin and providing a stable international framework will require difficult choices, including:
Committing NATO unambiguously to defend central Europe along a clearly defined line, and establishing tripwire troop presence to underline that commitment.
Establishing a body outside the UN Security Council, perhaps acting on its own as an adviser to the General Assembly, composed of countries respected for their support of international stability and the rule of law, that can issue non-vetoable opinions on short notice on whether a given military action by a nation violates international law or the UN Charter.
Establishing an international court of arbitration to which some disputes over natural resources might be referred.
Creating an international energy fund modeled on the International Monetary Fund that would have the capacity to extend emergency short-term energy assistance as well as the resources and know-how to help countries develop long-term policies for energy independence. (A similar function for food could be housed in existing international agencies, such as the World Food Program, with relatively minor modifications to their charter and function.)
The expansionist autocrats, including Putin, are asking themselves whether any countries are willing to back with force a post-Cold War system of rules and institutions that will limit "neighborhood" aggression and provide structures to contain disputes over food and natural resources.
This challenge requires more than the silence and incoherence the West has shown thus far.
Peter Goldmark, a former budget director of New York State, is a former publisher of the International Herald Tribune and headed the climate program at the Environmental Defense Fund.