Here are the main points of an important answer to that question by economist and former Wall Street honcho, Michael Hudson:
The six-nation Shanghai Cooperation Organization (SCO) is comprised of Russia, China, Kazakhstan, Tajikistan, Kyrghyzstan and Uzbekistan, with observer status for Iran, India, Pakistan and Mongolia. It was joined recently by Brazil, for trade discussions among the BRIC nations (Brazil, Russia, India and China), all of which seek a multi-polar world.
If it's not a move to make US hegemony obsolete, then what's the purpose of this new organization? US diplomats may well wonder. After all, this is exactly what a multi-polar world means: no hegemony by any one country. Another clue as to what's about to happen: in 2005 the SCO asked Washington to set a timeline to withdraw from its military bases in Central Asia.
It seems that the US has inadvertently driven Russia, China and their neighbors to find common ground by developing an alternative to the dollar as a dominant or reserve currency, and hence an end to the US ability to run balance-of-payments deficits ad infinitum.
Mr. Medvedev called for China, Russia and India to "build an increasingly multi-polar world order." What this means in plain English is: We have reached our limit in subsidizing the United States' military encirclement of Eurasia while also allowing the US to appropriate our exports, companies, stocks and real estate -- in exchange for paper money of questionable long-term worth!