KYIV, Ukraine — Ukraine’s former chief prosecutor, Yuriy Lutsenko, was a central figure in the events leading to the first impeachment of President Donald J. Trump, when Mr. Trump was accused of withholding military aid from Ukraine in an effort to persuade President Volodymyr Zelensky’s administration to investigate Hunter Biden.
Mr. Lutsenko, an opposition party member who now serves as a military officer, emerged from the impeachment trial in 2019 a tainted figure in Ukraine. As the prosecutor general under Mr. Zelensky’s predecessor, Mr. Lutsenko had met with Mr. Trump’s lawyer Rudolph W. Giuliani, and had discussed starting an investigation of Hunter Biden, President Biden’s son.
So when Mr. Lutsenko received a military promotion last month, it raised some eyebrows in Kyiv. Some saw it as a tone-deaf provocation of the Biden administration, sure to irritate Mr. Zelensky’s aides at a time when the Ukrainian Army is deeply dependent on military aid from the United States.
Then last week, Mr. Lutsenko abruptly lost his new assignment as the commander of a platoon of drone operators near the embattled city of Bakhmut. That prompted accusations of political retribution and raised the possibility of friction not just between Ukraine’s political parties, but between Mr. Zelensky and his military leadership as well.
Mr. Lutsenko himself was quick to float the possibility that Mr. Zelensky’s office had meddled with his promotion because of his position in the opposition party. “This little political revenge will not make Ukraine stronger,” Mr. Lutsenko wrote on Facebook after he was stripped of his command. “It’s high time to work on unity.”
Mr. Zelensky’s office did not respond to a request for comment on Mr. Lutsenko’s military appointments.
Fellow soldiers have rallied to Mr. Lutsenko’s defense, arguing that whatever his role in political squabbles in Ukraine in the past, he has redeemed himself by fighting on one of the most dangerous sections of the front line.
Ukraine’s raucous politics have been largely put on hold during the war. Opposition politicians have rallied behind Mr. Zelensky as commander in chief, even if they quietly criticize some of his policies. Many politicians, from both pro-government and opposition parties, volunteered to fight in the Ukrainian Army.
Mr. Lutsenko is a member of European Solidarity, a party led by Mr. Zelensky’s chief opponent in the 2019 presidential elections, former President Petro O. Poroshenko.
Before the war, Mr. Zelensky had drawn criticism for seeming to hold a grudge against Mr. Poroshenko, even after defeating him in the election. Their rivalry had dominated Ukrainian politics.
Volodymyr Ariev, a European Solidarity member of Parliament, said in a telephone interview that the reversal of Mr. Lutsenko’s military promotion “gravely concerns” him. “It’s clearly a politically motivated decision,” he said.
Before Mr. Trump’s interest in having Ukraine investigate Hunter Biden became public, Mr. Lutsenko, then serving as prosecutor general under Mr. Poroshenko, had met with Mr. Giuliani and discussed an investigation of Hunter Biden.
In testimony that emerged in the impeachment trial, Mr. Lutsenko was cast as a supporter of Mr. Giuliani’s plan, which Democrats said was intended to help Mr. Trump in the 2020 election. Mr. Lutsenko has said that he met with Mr. Giuliani to discuss other law enforcement issues and had declined to investigate Hunter Biden.
