Prime Minister Narendra Modi’s brief stop in the United Arab Emirates en route to Europe this week comes amid growing uncertainty over the fragile ceasefire between the United States and Iran and the danger of an intensifying regional war. Modi’s presence in Abu Dhabi underlines an enduring principle of sound diplomacy: Stand by your partners when they need you. Cynics will argue that no relationship is permanent. But when two countries are bound by deep economic interests, share stakes in regional stability, and support each other’s core interests, there is no room for Indian hesitation in demonstrating solidarity. The UAE has emerged as one of India’s most important partners. It is a major supplier of energy, a growing source of investment, and home to millions of Indians whose contributions bind the two countries in ways that go far beyond formal agreements.…