VLADIMIR PUTIN may have done John Kerry a very big favor. When the former KGB agent threatened Yukos with closure for failure to pay the $3.4 billion in taxes he discovered it owed when Yukos’ principal shareholder became a political opponent, oil prices temporarily hit a 21-year high. Never mind that any sensible observer knows that Russia’s treasury would drown in red ink, and the ruble collapse, if Yukos–which accounts for 20 percent of Russia’s current oil production and one-third of the recent increase in output–were forced to suspend export operations for any protracted period.