India is the world’s most populous country, the Voice of the Global South, and a major power that’s pivotal to the global balance between all key players so getting on its bad side like Zelensky just did will capsize Ukraine’s plans to generate wider support for its cause.

Zelensky insulted Indian Prime Minister Modi during his trip to Moscow last week by tweeting that “It is disheartening to see the leader of the world's largest democracy embrace the world's most not...