UNITED NATIONS — As world leaders gather at the U.N. this week, the U.S. and its European allies are consumed by efforts to blunt the savage advance of the Islamic State group, to end the raging Ebola epidemic and to make progress in nuclear negotiations with Iran. That’s likely just fine with Vladimir Putin, since these issues distract from Russia’s presence in neighboring Ukraine.

While attention focuses elsewhere, the Russians are consolidating their annexation of the Crimean Peninsula. They are also deeply involved in turmoil in Ukraine’s east and south, hoping to prevent the country from moving out of the Kremlin’s orbit. Europe and the United States insist the independent nation must be free to choose its own course.

Russia is already enraged over NATO’s having brought former Soviet satellite nations in Eastern Europe and some Baltic nations, once Soviet republics, into the alliance over the past two decades. The Kremlin insists it was promised, after the dissolution of the Soviet Union, that that would not happen. It’s doing its best to prevent Ukraine from making the same move.