In the span of just a few days, the global economic outlook has darkened while troops battled in Ukraine and unexpectedly potent financial sanctions rocked Russia’s economy and threatened to further fuel worldwide inflation.The price of oil, natural gas and other staples spiked on Monday. At the same time, the groaning weight on supply chains, still laboring from the pandemic, rose as the United States, Europe and their allies tightened the screws on Russia’s financial transactions and froze hundreds of billions of dollars of the central bank’s assets that are held abroad.Russia has long been a relatively minor player in the global economy, accounting for just 1.7 percent of the world’s total output despite its enormous energy exports. President Vladimir V. Putin has moved to further insulate it in recent years, building up a storehouse of foreign exchange reserves, reducing national debt and even banning cheese and other food imports from Europe.But while Mr. Putin has ignored a slate of international norms, he cannot ignore a modern and mammoth financial system that is largely controlled by governments and bankers outside his country. He has mobilized tens of thousands of his troops, and, in response, allied governments ha …
