New Delhi, July 25 -- In the span of a single week, the dismissal of a Ukrainian defense minister set in motion a transformation of the country's armed forces that replaced the old guard with a new generation of leadership.

Ukrainian President Volodymyr Zelenskyy's decision to fire his popular defense minister, Mykhailo Fedorov, triggered days of public protest that quickly shifted toward the country's commander-in-chief and highlighted the growing rift over the future of Ukraine's military.

Demonstrators denounced the commander, Oleksandr Syrskyi, and overwhelmingly rallied behind the departed defense minister, who has emerged as one of the country's most influential wartime reformers with support from Ukrainians hungry for change. Pro...