The key roles played by Japan and South Korea in this year’s Rim of the Pacific (Rimpac) military exercises led by the US have fuelled speculation whether the two neighbours could set aside differences over their common history and deepen defence cooperation. Held in waters off Hawaii, this year’s Rimpac is the world’s largest maritime exercise involving 30 nations, more than 30,000 troops, various aircraft and an armada of surface ships and submarines. Rimpac, which runs from June 24 to July...