It’s hard to overemphasize Gazprom’s role in the Russian economy. It’s a sprawling company that raked in $91 billion last year; it employs 432,000 people, pays taxes equal to 20 percent of the Russian budget and has subsidiaries in industries as disparate as farming and aviation. ... When Mr. Putin was still president, he used Gazprom’s wealth and economic might to fight political enemies inside Russia, to reassert influence over former Soviet republics, to gain leverage over Western European countries by increasing their dependence on Russian gas, and to wrest Russian energy assets back from foreign companies. ...Mr. Putin denied...