Last week's summit among the leaders of Brazil, Russia, India, and China occasioned predictable analyses of the dawn of a new world order led by these developing giants. Their scale is indeed breathtaking. Each is subcontinental in scope; together they represent nearly every region; their combined GDPs may surpass those of the G7 within two decades; and between them they boast nearly half the world's population. They possess complementary advantages. China is a manufacturing superpower; India is the world's largest democracy and "knowledge power"; Russia is a potential "energy superpower," according to the U.S. National Intelligence Council; and Brazil dominates a region lacking any great power competitor. An alliance among these behemoths could change history in ways that diminish the West.

But in many ways, these countries are more rivals than partners. India's national security planners identify China as their most important adversary, and bilateral tensions have grown even as two-way trade has multiplied. Russia defines itself as a European power and feels threatened by China's rise, particularly given the challenge of defending the mineral-rich Siberian heartland from creeping Chinese economic colonization. Russia, China, and India compete vigorously for influence in Central Asia, as do China and India in South and Southeast Asia and in markets for natural resources worldwide. Brazil has important commercial relations with China, but their political regimes could not be more different. Leaders in both Brazil and India have invested much more in a trilateral partnership with South Africa that unites them in an alliance of values spanning three continents.

Nor are the economic interests of the BRICs as complementary as they might appear. Although it suffers from acute misgovernance, Russia is an industrialized country that sits on the UN Security Council and in the G8; it is not a developing state excluded from great power clubs. Russia is also a declining power rather than a rising one -- its demographic and social indicators are ruinous, and its energy-dominated economy is ill-equipped to compete with the innovation and manufacturing prowess of the Asian giants. Brazil is a middle-income country that experienced in the 1970s the economic takeoff China and India are now enjoying; its moderate growth rates and industrial structure put it in a different league, and constrain the speed of its further rise.

The economic asymmetries don't stop there. India's consumption-driven, private-sector-led, services-oriented economy is the converse of China's export-driven, state-dominated, mass-manufacturing economy. China's artificially cheap currency handicaps the export prowess of the other BRICS. That's why their finance ministers were quick to side with the United States before this week's G20 finance ministers' meeting in calling for China to allow the renmimbi to appreciate -- an "absolutely critical" requirement, declared Brazil's central bank chief, and an assessment echoed by his Indian counterpart.

Partly as a result of these rivalries and differences, each of the BRICs (with the partial exception of Brazil) covets closer partnership with the West -- and prioritizes those relations above ties to each other. Each views its ties to the United States as its most important bilateral relationship. Each works to maximize investment in and trade with the developed markets of Europe. Trade with the West is in many ways more complementary and mutually beneficial than their structurally imbalanced trade with China -- in which Brazil, Russia, and India export raw commodities and import low-cost manufactures. These relations are not entirely unlike the unequal and extractive nature of economic exchange that characterized relations between the European empires of yesteryear and their overseas colonies.

Moreover, it is more likely that geopolitical competition in the 21st century will occur between rising powers like China and India -- or will pit revisionist states like China against established powers like America -- than that the future strategic landscape will divide between a BRIC bloc and the West. Countries like India, Brazil, and Russia have too much at stake in their relations with North America and Europe, and remain too wary of the Chinese colossus, to make Beijing their alliance partner of choice. And we should not overlook another set of ascending powers -- South Korea, Indonesia, Mexico, and South Africa -- all democracies with strong ties to the West and, as their membership in the G20 shows, emerging global players.

These rising powers are knocking at the door of global governance frameworks and institutions. Are Western nations willing to let them in? Are they willing to invest in relations with potentially like-minded countries such as India -- and at a level of quality and intensity that the transatlantic allies previously reserved only for each other? Failure on either front would give the BRICs a lot more in common than they have now.