With Donald Trump mulling an invasion of Iran, Vladimir Putin threatening to nuke Ukraine, and America’s last remaining arms-control treaty with Russia expiring earlier this month with little prospect of renewal, I find myself pondering two eternal questions. One involves a chicken; the other, Julius Caesar. In both instances, we are asked: Why? Why did the chicken cross the road? Why did Julius Caesar cross the Rubicon? What were they thinking? Or: Were they thinking?