This is a world without rules. You won’t discover whether one country should become involved in the affairs of another by reading the United Nations Charter, and now that the cold war is over it’s hard to deduce whether intervention is justified by a search for that holy grail, “the national interest.” “We are confronted with 10 or 20 situations,” U.N. Secretary-General Boutros Boutros-Ghali told Newsweek. “To solve them costs only 2 or 3 percent of what the cold war cost. But there is not the political will to do so.” Some countries do find the will. Here’s a short guide to who, where – and why.

Some nations, for reasons of habit or history, are wary of ventures beyond their borders even when they’re strong enough to undertake them. The classic cases are the defeated powers of World War II, Germany and Japan, which have had constitutional bars against foreign meddling. True, both have dipped their toes in the water of intervention, Japan by contributing to the U.N. mission to Cambodia, Germany in Somalia. But even though the German Constitutional Court has given German forces a new freedom to travel, neither country is likely to be adventurous any time soon. Mexico is another habitual Wallflower; so is Switzerland. South Africa, which sees little virtue in being asked to police Africa, may be a new Wallflower. An increasingly skittish Britain may join the group.

Whenever a nation sends troops abroad, it will say it does so for “humanitarian” reasons, or because of the need for “stability” in a troubled region. Here’s a rough rule of thumb: believe such claims when they’re made by Canada, Australia or the Scandinavian countries. Otherwise, be skeptical. France’s intervention in Rwanda last month simply “has to do with French glory,” says Alison Desforges of Human Rights Watch. Even in Paris, there has been a hot debate about whether France was genuinely motivated by humanitarian concerns or by a desire to maintain a Francophone sphere of influence. Benign intentions aren’t what counts, though. The United States had the best of motives in Somalia, and little good that did. And don’t confuse Do-Goodery with weakness. In Bosnia, the Scandinavian troops have been among the toughest of the U.N. forces.

This used to be the most common motive for interventions – whether it was to secure minerals or save some poor citizen marooned in a foreign hellhole (once a U.S. favorite). Now, in its pure form of sending troops to the far side of the world to secure or maintain a sphere of influence, imperialism is out of favor with everyone but the French. True, in 1982 Britain sent a battle fleet to the Falklands – but they were still a British colony. The next year Britain disapproved of intervention in Grenada, an ex-colony. France, on the other hand, has shown no compunction about sending troops to its old territories in Africa – as it did in Chad, for example, in 1992. But France would like to share the burden. Defense Minister Francois Leotard recently called for establishing a Pan-European rapid-reaction force for Africa; other Europeans wondered what he’d been smoking.

The modern heirs to the Imperial Twitch, they practice intervention to defend some “vital interest” close to home. In this category: the U.S. operations in the Dominican Republic in 1965 and Panama in 1989, and the current Russian meddling in the Caucasus. India developed a taste for Backyardism in the 1980s (Sri Lanka, the Maldives). But the next big Backyard Bully will likely be China, which last week again warned Vietnam off the oil-rich Spratly Islands in the South China Sea.

How do today’s events fit this taxonomy? Not very neatly. Even if the original French intervention in Rwanda was a case of the Imperial Twitch, the horrors there have now clothed France’s involvement with the aura of Do-Goodery. Haiti is the opposite case. If America intervenes there, it will do so in a rare bout of genuine Do-Goodery – and quickly be accused of being a Backyard Bully. In a climate that Boutros-Ghali says is typified by “indifference, neo-isolationism and fatigue,” it’s enough to make a Wallflower out of anyone. Ask those Do-Gooders so desperate to leave Bosnia.

Rwanda, Haiti and Somalia command the most attention, but other nations throughout the developing world are in crisis. Among them:

Civil war decimated agriculture. Life expectancy, literacy among world’s lowest.

Warfare blocks exploitation of natural resources, threatens outbreak of mass famine.

Social dislocation from a long civil war leaves the former Portuguese colony with food shortages and refugee woes.

Military regime is fighting a multifront ethnic war. A third of young children malnourished.

Famine leads to staggering mortality rates as north-south conflict continues.

Near paralysis in ex-Soviet republic due to tribal, religious and political warfare.

Ethnic clashes have displaced almost a million people and fragmented the government.

Despite natural-resource base, more than half the population lives in absolute poverty.