India, Sept. 12 -- Diplomacy is usually conducted across polished tables. Increasingly, it is also conducted in the back seat of an armoured limousine.

On Friday, Prime Minister Narendra Modi and Russian President Vladimir Putin closed bilateral talks on the eve of the 18th BRICS Summit. Then they travelled together in Putin's Aurus Senat to the INNOPROM exhibition at Bharat Mandapam.

In Delhi, the choreography was shorter but no less pointed: two leaders who have met twice in a fortnight choosing the same sealed cabin rather than separate official cars. The talks themselves were businesslike. Trade, energy, defence, civil nuclear cooperation, critical minerals, railways and industrial projects featured on the agenda, along with the $10...