Singapore’s decision to send its top diplomat to Indonesia on a surprise visit, following days of terse exchanges over a regional haze, underscores a bid to defuse growing tensions and seek a direct channel to President Prabowo Subianto. Analysts say Foreign Minister Vivian Balakrishnan’s trip reflected his country’s preference for measured diplomacy amid rising nationalistic rhetoric in Indonesia, with the city state also mindful of containing any “negative fallout” as Jakarta grapples with...