In his zealous efforts to popularize drone warfare, Ukraine’s young defense minister, Mykhailo Fedorov, also gained widespread popularity himself.
And that, political analysts and opposition politicians said, may have helped bring about his downfall this week, as President Volodymyr Zelensky sided against him in a titanic clash with the country’s top military commander.
Mr. Zelensky’s dismissal of Mr. Fedorov, 35, sidelined a potential political rival who had seized the spotlight. Timing of his ouster is awkward, just as drone warfare has helped tilt the scales in Ukraine’s favor. The move also indicates Mr. Zelensky’s misgivings about Mr. Fedorov’s vision of drones as nearly the entirety of the country’s future in fighting the war.
The firing of Mr. Fedorov came after he had blocked purchases of artillery ammunition in favor of drones. The commander of Ukraine’s military, Gen. Oleksandr Syrskyi, had insisted that the ammunition was still needed in the brutal trench fighting in the country’s east.
“The popularity of drones is the problem” that led to Mr. Fedorov’s ousting, said Mykola Davydiuk, a member of Parliament in the opposition Holos party.
Mr. Fedorov had become “a problem and a danger” for Mr. Zelensky, Mr. Davydiuk said, by championing a purely technological overhaul of Ukraine’s military that was widely popular but was opposed by the top general actually fighting the war.
Politically, the firing fit a pattern in which Mr. Zelensky has sidelined potential rivals during the war, though none, including Mr. Fedorov, had publicly voiced political ambitions. Political advisers, Mr. Davydiuk said, had convinced Mr. Zelensky that Mr. Fedorov had stolen public attention with the drone program.
Mr. Zelensky ousted Mr. Fedorov even though the move confused and angered many Ukrainians, thousands of whom have taken to the streets to demand his reinstatement. The move also threatened to disrupt the war effort, including the ties that Mr. Fedorov had built between the military and the drone industry, analysts said.
Speaking to reporters in an underground parking garage in Kyiv, the capital, on Thursday, Mr. Fedorov said that General Syrskyi had presented an ultimatum to Mr. Zelensky. That brought to a head a debate in Ukraine — the country at the leading edge of drone warfare — over whether reliance on drones had gone too far.
Mr. Fedorov has been a leading proponent of deploying small robotic systems that could replace infantry, artillery and armored vehicles in some roles, evening the odds for Ukraine against Russia’s larger army. Increased drone purchases by his ministry during his six-month tenure coincided with a stabilization of the front and a campaign that wiped out about a quarter of Russia’s oil refining capacity.
But while exploding drones now inflict about four-fifths of all casualties on both sides, they fly poorly in foggy or windy weather, when artillery remains effective. Critics within the military have dismissed Mr. Fedorov’s ideas about robot warfare as fanciful. Soldiers still need to hunker in muddy, rodent-infested bunkers to fight off Russian advances.
Mr. Fedorov, in his explanation of the falling-out over strategy, also pointed to vested interests in the arms industry. He said his overhaul of procurement to favor drones had threatened business interests.
“We were supposedly behaving very badly as a state because we were disrupting a company’s business strategy,” Mr. Fedorov said.
A key dispute in the months before Mr. Fedorov’s removal revolved around purchases of traditional military hardware, according to Mr. Fedorov, an arms industry executive and Ukrainian media reports. The executive spoke on the condition of anonymity because he was not authorized to speak publicly.
Speaking on Thursday, Mr. Fedorov acknowledged that he had ruffled feathers by canceling or opening bids for purchases of the most common ammunition, 155-millimeter NATO-caliber artillery shells, while halting all purchases of short-range versions of these munitions.
He said he had saved $100 million in doing so. He also insisted that Ukraine would still buy longer-range shells. Aides to Mr. Fedorov, however, wrote to military contractors in recent months to say that the defense ministry would buy no more artillery munitions of any type, relying instead on stockpiles and drones, according to the defense industry executive.
That caused a rift because in Ukraine, the military’s general staff, led by General Syrskyi — not the defense ministry — sets priorities for weapons purchases.
General Syrskyi is a gruff-spoken commander known within the army as “the Butcher” for his willingness to take casualties.
While Mr. Zelensky sided with the general in his clash with Mr. Fedorov, the president indicated to members of his political party at a meeting this week that it had been a difficult decision, Ukrainska Pravda, a major Ukrainian newspaper, reported.
Mr. Zelensky told his party members that he had, in fact, wanted to fire both men and start fresh, the newspaper reported, but could not make the moves all at once.
An aide to Mr. Zelensky said on Friday that the president was in talks with Mr. Fedorov for a new role within the government. Mr. Fedorov said the day before that he had turned down job offers from Silicon Valley companies after his firing.
General Syrskyi, 60, is not seen as harboring postwar political ambitions. Mr. Zelensky has moved, however, against other military leaders considered as posing a political challenge.
Earlier in the war, he fired the commanding general of the military, Gen. Valeriy Zaluzhny, whose popularity rating at times exceeded the president’s and who was widely viewed as a potential challenger in a postwar election. Mr. Zelensky appointed him as ambassador to Britain.
Before that move, commentators warned of disruptions in the army if General Zaluzhny were fired, but the leadership handover to General Syrskyi went smoothly.
In January, Mr. Zelensky moved Gen. Kyrylo Budanov, who had led Ukraine’s military intelligence service, into his office as chief of staff. Political analysts saw the shift in part as intended to keep the general close politically, complicating any potential run for the presidency after the war.
With Mr. Fedorov now joining them in being sidelined, supporters of his digital-minded approach to war lamented his dismissal in street protests in Kyiv and other cities. “Return to Fedorov!” many cardboard signs read.
One sign pointedly noted that the protests could grow. “We have a hell of a lot of cardboard,” it said.
Nataliia Novosolova contributed reporting.