KYIV, Ukraine (AP) — The man Ukrainian President Volodymyr Zelenskyy named Thursday to lead the country's military has played a key role in some of Ukraine's biggest victories in its war with Russia, including overseeing the successful defense of the capital in the early days of the invasion. Col. Gen. Oleksandr Syrski, who had been commander of Ukraine’s ground forces, takes over the head job at a challenging time. With the war poised to enter its third year, morale is low, the military is facing shortages of ammunition and personnel, and Kyiv is struggling to maintain support from the West.