... Big news just came down the pike. Courtesy of a friend, I learn that Poland has agreed to host US ballistic-missile defenses. As geopolitical lines harden, the question becomes if Russia's actions will drive a wedge between NATO members that embrace a harder or a softer line towards Russia. Or will balance-of-threat dynamics lead to renewed NATO cohesion? I suspect the answer is far from preordained: a great deal depends on how US and...