With the fall of the Soviet Union, its former constituent republics were faced with multiple diplomatic, economic, environmental, legal, military, political, and social issues.
The end of the Soviet Union resulted in the eruption of multiple boundary and sovereignty disputes, including wars in Chechnya and Transdniester.
Left ambiguous and unresolved was the fate of Crimea in Ukraine, and the status of the highly militarized city of Sevastopol, home of the Soviet Black Sea fleet.
The Soviet Union operated under a command economy (as opposed to a market economy). Once central planning as directed from Moscow stopped, the economies of the constituent republics were thrown into turmoil.
Much of the Soviet civilian infrastructure was badly built in the first place, resulting in many roads, bridges, pipelines, power lines, and buildings rotting in place.
Soviet law prohibited capitalism, or at least made free markets subject to heavy bureaucratic restrictions.
The nomenklatura (the ruling technocratic elite) remained in charge of collectivized farms and industrial facilities, since there were no mechanisms in place for the transfer of power and managerial authority to anyone else.
As in many of the constituent republics, Ukrainian Oligarchs seized control of the means of production.
Several million heavily armed military, militia, and paramilitary soldiers were left without a clear chain of command, and in many cases without pay.
A market for illicit weapon sales grew rapidly.
Nuclear missiles were left poorly guarded.
Various republics declared independence.
The Communist Party lost most of its membership rapidly.
Competing political parties, including rabid nationalists, sprang up quickly.
The social safety net for pensioners disappeared.
Criminal activity, alcoholism, and corruption flourished.
Many of the Soviet dead, lost to war, famine, purges, resettlement, and the gulag, remained unaccounted for.
"Imperium" by Ryszard Kapuscinski, Vintage Books, 1995 $15 350 pages ISBN 067974780X
"Black Earth: A Journey Through Russia After The Fall" by Andrew Meier, Norton & Company, 2003 $16 500 pages ISBN 0393326411