Standing in the nerve center of Gazprom’s Moscow headquarters — staring at a 100-foot wall that electronically displays the spiderweb of natural-gas pipelines spreading across Europe from Russia — Mr. Goldman marvels: “What an empowering feeling! Should they choose to, those Gazprom functionaries could not only cut off natural gas from the furnaces and stoves of 40 percent of Germany’s homes but also the natural gas that many German factories need for manufacturing.” In other words, Ronald Reagan’s warnings in the 1980s, about the political dangers of Western Europe’s dependence on Soviet gas, now seem prescient. Today Western Europe relies on Russia for half of its natural-gas imports. (…) The unanswerable question is whether the Kremlin — or more precisely, Vladimir Putin — will use gas as a weapon to gain international political influence. The optimistic view is that business normalizes politics — in this case, that Russia’s need to be a dependable partner will require it to soften its political edge and conform to international standards of behavior. Pessimists fear that gas dependency will lead to the Finlandization of Europe. On the evidence so far, the pessimists have the better chance of being right.