Japan appears to be edging ever closer to a referendum on its pacifist constitution, after a realignment of parliamentary forces delivered the supermajority needed to put the change to a public vote. For nearly eight decades, Article 9 of the 1947 constitution – drafted under Allied occupation and long treated as untouchable – has prevented Tokyo from formally maintaining a military with “war potential”. That article has outlasted every previous attempt to change it. But Japanese conservatives...