It’s not surprising that the regime of Mr. Medvedev and his master, Vladimir Putin, would be the first to try intimidating the president-elect, though the speed with which it did so might have surprised even Mr. Biden. (…) We expect that Mr. Obama will be smart enough not to fall for this. He’s already made it clear that he intends to stand against Russia’s aggression in Europe. We share some of the doubts about the missile deployment — but if it is slowed or canceled, it should be done without reference to Moscow. Unlike some of the probes that will be aimed at Mr. Obama in the coming months, Russia’s latest crude threat can be neutralized simply by denying it the attention that Mr. Putin craves.