The US Must Prepare for War Against Russia Over Ukraine

President Vladimir Putin is more likely than not to invade Ukraine again in the coming weeks. As someone who helped President Barack Obama manage the U.S. and international response to Russia’s initial invasion of Ukraine in 2014, and our effort to keep Moscow from occupying the whole country into 2015, I am distressingly convinced of it. 

Why? I see the scale and type of force arrayed by the Russian military, the ultimatums issued by Putin and his officials, the warlike rhetoric that has until recently saturated Russian airwaves, and the impatience with talks expressed by his foreign minister....