The Senkakus issue is likewise a symptom of tensions whose cause lies elsewhere, in China’s growing challenge to America’s long-standing leadership in Asia, and America’s response. In the past few years China has become both markedly stronger and notably more assertive. America has countered with the strategic pivot to Asia. Now, China is pushing back against President Barack Obama’s pivot by targeting Japan in the Senkakus.

The Japanese themselves genuinely fear that China will become even more overbearing as its strength grows, and they depend on America to protect them. But they also worry whether they can rely on Washington as China becomes more formidable. China’s ratcheting pressure over the Senkakus strikes at both these anxieties. …

Where will it end? The risk is that, without a clear circuit-breaker, the escalation will continue until at some point shots are exchanged, and a spiral to war begins that no one can stop. Neither side could win such a war, and it would be devastating not just for them but for the rest of us.