The old Soviet Union, in stark contrast, was all but impervious to foreign economic or business pressure, thanks in part to an ideological commitment to self-sufficiency. As recently as 1985, foreign trade amounted to just 4 percent of the country’s gross domestic product, and nearly all that was with the communist satellite countries of Eastern Europe. But the Soviet Union’s economic insularity and resulting economic stagnation was a major cause of the Soviet Union’s collapse. According to Mr. Talbott, the Soviet Union’s president at the time, Mikhail Gorbachev, was heavily influenced by Soviet economists and other academics who warned that by the turn of the century in 2000, the Soviet economy would be smaller than South Korea’s if it did not introduce major economic reforms and participate in the global economy.

To attract investment capital, Mr. Gorbachev created the Moscow stock exchange in 1990 and issued an order permitting Soviet citizens to own and trade stocks, bonds and other securities for the first time since the 1917 Bolshevik revolution. (Before then, Russia had a flourishing stock exchange in St. Petersburg, established by order of Peter the Great. It was housed in an elegant neoclassical building directly across the waterfront from the Winter Palace. As a symbol of wealth and capitalism, it was one of the earliest casualties of the revolution.)

Even before this week’s gyrations, the Russian stock market index had dropped near 8 percent last year, and it and the Russian economy have been suffering from low commodity prices and investor concerns about the Federal Reserve’s tapering of bond purchases — factors of little significance during the Cold War.

By contrast, today “Russia is too weak and vulnerable economically to go to war,” Mr. Aslund said. “The Kremlin’s fundamental mistake has been to ignore its economic weakness and dependence on Europe. Almost half of Russia’s exports go to Europe, and three-quarters of its total exports consist of oil and gas. The energy boom is over, and Europe can turn the tables on Russia after its prior gas supply cuts in 2006 and 2009. Europe can replace this gas with liquefied natural gas, gas from Norway and shale gas. If the European Union sanctioned Russia’s gas supply to Europe, Russia would lose $100 billion or one-fifth of its export revenues, and the Russian economy would be in rampant crisis.”