As Donald Trump and Kim Jong un meet in Vietnam to defuse nuclear tensions on the Korean peninsula recrudescence between nuclear armed India and nuclear armed Pakistan has escalated on the subcontinent. It began with a cross-border suicide bomber in Kashmir killing dozens of Indian soldiers. India responded with cross-border aerial incursions, the first in decades, that seemed designed to do nothing but plow remote mountain fields. But today Pakistan has shot down an Indian plane or two and has paraded a pilot as captive.

These two foes have a practised routine of tit for tat that each understands is to prevent escalation. Parading captive pilots is not recognized as part of that routine.