Just before he sat down to a traditional Bavarian meal of sausages and beer with German Chancellor Angela Merkel at the start of the Group of Seven summit on Sunday, U.S. President Barack Obama told the media that one of the meeting's priorities would be discussing ways of "standing up to Russian aggression in Ukraine." Which begs the question: what kind of aggression are we talking about here?
There are unquestionably Russian troops in the rebel provinces of eastern Ukraine, and that is certainly an act of aggression under international law. (The Russian troops there are definitely not just volunteers lending the rebels a hand while they are on leave, as Moscow maintains. How can we be sure? Because soldiers on leave do not take their tanks and artillery with them.)
But is this a prelude to a Russian invasion that would take over all of Ukraine, as Ukrainian President Petro Poroshenko recently alleged? If it is, it would require a whole different level of response, and the result could easily be a new Cold War.