The 1980s oil crisis led to the end of the old Soviet Union

Oil’s decline is proving to be the worst since the collapse of the financial system in 2008 and threatening to have the same global impact of falling prices three decades ago that led to the Mexican debt crisis and the end of the Soviet Union.
Russia, the world’s largest producer, can no longer rely on the same oil revenues to rescue an economy suffering from European and U.S. sanctions. Iran, also reeling from similar sanctions, will need to reduce subsidies that have partly insulated its growing population. Nigeria, fighting an Islamic insurgency, and Venezuela, crippled by failing political and economic policies, also rank among the biggest losers from the decision by the Organization of Petroleum Exporting Countries last week to let the force of the market determine what some experts say will be the first free-fall in decades.

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Oil Shock Streaks Across Globe From Moscow to Tehran to Caracas. Ready for $40?

Then as now Saudi Arabia and OPEC were behind the drop in the 1980s to 12 dollars a barrel then which was one of the factors along with Chernobyl and the Soviet Union defeated in Afghanistan by American missiles fired by Osama Bin Laden and his Mujahedeen  fighters against Russia helicopters, fighter jets and Tanks.  This combination of events and Gorbachev being the leader then led to the fall of the Iron Curtain and the Reduction of Russia to it's present size today.