Randall Forsberg’s smart, perceptive diagnosis of the state of the international system is about right, in my opinion. But her prescription, while good as far as it goes, is in my view incomplete. At several points in her essay she correctly attributes the decline in major war between countries to three great changes: military technology, increasing wealth, and the democratization of political values and institutions. Her prescription to extend this decline, however, focuses overwhelmingly on measures of arms control and disarmament, with scarce attention to enhancing the other beneficial changes.

It may well be that the great powers can and will reduce their own arsenals of mass destruction, in a way that will reinforce one another’s wish to do so and serve as an example to lesser powers. Possibly they can even reach collective agreements to reduce arms sales to lesser powers whose enhanced military capabilities, Forsberg sagely notes, ultimately constitute the greatest short- and medium-term threat to the great powers’ interests. But the portents for such restraint are not terribly good. It certainly would require an effective pact among the great powers, one that could resist strong and ever-present temptations to cheat. After all, the standard response to calls for restraint in the arms trade is, “If we don’t sell it the British (French, Germans, Russians, whoever) will.” And there is a lot of truth to that response. It carries special bite if the great powers’ own arms purchases, from their own industries, are declining. Then the pressures of the military-industrial complex to keep the arsenals open and the workers employed are especially hard to resist.

If we want to stop war we need to look beyond the military to the economy.

If the international circumstances of reduced security threats around most of the globe seem propitious for such restraint, so too do economic conditions in the industrialized world. For Europe (save Russia) and even Japan, economic good times continue. If economic expansion has slowed, even to a near-halt in some states, conditions are still far better than in worldwide recession or depression, which we may yet see. Because these circumstances seem propitious, the results in the United States are particularly disheartening. The American economy remains on a roll. The military budget is not declining, and a decent (or indecent) stream of new orders to U.S. arms industries continues to come in from the rest of the world. Yet at the same time the administration lifts the embargo on the sale of advanced weapons to Latin America. If this is what happens in prosperity, what will happen in recession, when unemployed arms producers cannot readily find alternative activities? Or when, as Forsberg and I hope, the U.S. military really does shrink significantly.

It is essential, therefore, to broaden the prescription beyond the military dimension. Like medical researchers, we can look at the “epidemiology” of military conflicts in the world to understand their causes. Like epidemiologists, we can study a very large number of cases of peace and conflict. For example, we can look at all pairs of countries in the world over much of the post-World War II period. We can ask whether any particular pair experienced a military dispute (threat or low-level use of military force, not just a war) in any particular year. We must look at low-level disputes as well as wars, because most wars—rare events which are hard to generalize about—begin as escalated disputes. All these cases—of peace as well as dispute—give us about 200,000 “cases” to consider. Analysis of this information, inspired by theory and some intuition, shows this:

After one takes into account the role of deterrence and military balances, two of the other influences that Forsberg mentions stand out as big restraints on the likelihood that two countries will get into a situation whether they threaten to shoot at each other, or actually do.

First, it makes a big difference if both are democratic. A very democratic and a very autocratic country were more than two-and-a-half times more likely to get into a militarized conflict than were two very democratic countries. And in this period, there were no wars between full democracies. (Most of the civil wars, and all the cases of genocide, also occurred in countries with autocratic or totalitarian governments.)

Economics also made a great difference. If two countries were highly interdependent (their mutual trade accounted for a substantial portion of their GNPs), they were again about two-and-a-half times less likely to have a military dispute than if they traded little or at all. This was an even greater disincentive than simply being wealthy, and the reasons are pretty clear. If we bomb the cities or factories of a close trading partner—where we also are likely to have heavy private investments—we are bombing our own markets, suppliers, and even the property of our own nationals.

A very democratic and a very autocratic country were more than two-and-a-half times more likely to get into a militarized conflict than were two very democratic countries.

One additional influence is worth noting. International organizations reduce conflict in many ways. A few of them can actually coerce law-breakers; all can mediate conflicts of interest, convey information and assist problem-solving, and socialize governments and peoples to common norms and mutual identities. Countries that shared membership in many international organizations (a few of them universal organizations, most of them regional organizations for trade, security, development, or environmental protection) were also less likely to fight each other or threaten to do so.

Together, when these three influences (shared democracy, interdependence, and dense international organization networks) were strong, a pair of countries was 80 percent less likely to have a military dispute than was the average pair of countries in the world. These resultsrequire further analysis, but they appear to compare favorably with what we know, for instance, about which influences produce many cancers or heart disease. Further analysis also encourages me to believe that these relations are in fact causal. For example, countries are unlikely to fight because they trade, and not just vice-versa, and countries do not join international organizations only with other countries that are already their close friends.

Forsberg is probably right that the prospects for major conventional war in the next decade or so are small. For the mid- or longer-term, however, we need to think hard about supplementing the direct restraints on militarization. By sometime in the second decade of the next century China may well have a GNP (total, not per capita) equal to that of the United States. If China keeps growing rapidly after that, the two could become involved in the kind of deadly top-dog and second-dog rivalry that Forsberg identifies as a roughly every-50- year phenomenon. It would be especially dangerous if, as Forsberg warns, China continues to import high-level military technology from Russia and even forms an alliance with Russia. The “epidemiological” results suggest a way to handle that situation.

First, do our best to bring Russia firmly into the Western security system as its democracy and free-market commitments become more secure. If NATO is to expand, do not stop that expansion short of the border of a Russia that is making reasonable political and economic progress—to do so will drive it toward a tie with China. Second, do our best to bring China firmly into the world network of economic interdependence and international organization—it is in our interest as well as China’s.

Because China is not likely to democratize soon or rapidly, it is all the more important to strengthen the economic and institutional incentives that discourage a turn to military expansion. (The Chinese leadership has been far more willing to accept international pressures for economic than for political liberalization.) This will not be easy, nor always comfortable. But it is far wiser than relying primarily on a “preventive” military build-up to contain China. The result of that strategy could well be a self-fulfilling prophecy of conflict.

Some “rogue” countries will likely stay outside any system of pacific relationships that can be built. But if they are few, deterrence can be achieved with the lower levels of military capability that Forsberg advocates, and citizens will more readily accept and insist on lowering the levels.