The alliance was meant to be an eastern version of the European Union with Russia at the center of a global economic force. As it currently stands though, the Eurasian Economic Union -- which began in a ceremony Thursday in Astana, Kazakhstan -- has the geography to make it an important trade hub of goods passing between Europe and Asia.
It will be formally established on Jan. 1, 2015.
The union's missing member, Ukraine, hovered between joining the European Union or the new economic bloc until a national divide over the matter brought down its government in early 2013.
"We lost someone along the way, I mean Ukraine. Unfortunately this is not the agreement that our partners originally announced," said Belarus President Alexander Lukashenko. It was his hope the economic pact would be followed by political and military unity, an idea Kazakhstan rejected.
The union raises Russia's profile as a global trading power, secures its interests in the economies of at least two former Soviet Union states, and partially cements an ideology of an anti-Western economic union.
Putin, in a 2011 newspaper essay outlining the plan, denied it was a restart of the old Soviet Union -- a charge frequently made by his critics.
"Three weak economies getting together and integrating, how much good can come out of it?" said Nargis Kassenova of Kimep University in Almaty, Kazakhstan. "Now it is even worse because one is under [economic] sanctions and drifting away from the West," she said in a reference to Russia.