NATO leaders gathered in Washington are meeting the leaders of Japan, South Korea, Australia, New Zealand and Ukraine on Thursday, on the third and final day of a summit that marked the alliance’s 75th anniversary. On Tuesday and Wednesday, NATO leaders announced further military support for Ukraine’s efforts to repel the Russian invasion, including air-defence systems and a pledge to spend €40 billion ($43 billion) in the next year. They also declared Ukraine’s future path to NATO membership “irreversible.” The final day of the summit is devoted to external relations: first a meeting with the…