Ask Ukrainians who wields the most power after the president, and many would have said Andriy Yermak, President Volodymyr Zelenskiy’s chief of staff and a key negotiator throughout four years of war, helping Kyiv maintain Western support. That is no longer the case. Yermak, a longtime friend and trusted aide of Zelenskiy, resigned on Friday (Nov 28) after becoming embroiled in a growing corruption scandal, triggered when anti-graft authorities searched his property. At 54, he is the highest-profile figure to step down in the ongoing investigation, which has already claimed two ministers. His departure leaves Zelenskiy more politically isolated than at any point since Russia’s full-scale invasion.

The timing is critical for Kyiv, which faces US pressure to make major concessions to Moscow while lacking sufficient troops and weapons to repel Russian advances. Allegations of corruption among top Ukrainian political and business figures have eroded US confidence in Zelenskiy at a time when he needs it most. Oleksandr Merezhko, chair of Ukraine’s Parliamentary Foreign Affairs Committee, endorsed Yermak’s resignation, telling Reuters that the move “strengthens the president’s position in the eyes of parliament, society, and Western partners.”

Born in Kyiv, Yermak began his career as a lawyer before founding a media company. He and Zelenskiy met in the early 2010s, when Zelenskiy was a rising TV personality and Yermak was emerging in media. Yermak joined Zelenskiy’s presidential campaign in 2019 and quickly became a central figure in his administration. Whether in a suit abroad or khaki on the frontlines, Yermak was a constant presence beside the president, acting as Kyiv’s main contact with US administrations, coordinating prisoner exchanges and peace talks, and lobbying for weapons, funding, and sanctions against Moscow.

Details of the anti-corruption searches remain unclear, and Yermak has said he is fully cooperating. The investigations are linked to a scandal involving alleged kickbacks and money laundering worth roughly US$100 million at Ukraine’s state atomic agency, a particularly sensitive issue amid frequent Russian strikes on energy infrastructure. While Yermak has not been named a suspect, opposition lawmakers and even some members of Zelenskiy’s party had called for his dismissal.

Despite his departure, Zelenskiy remains popular, and letting go of a close ally could reinforce his commitment to combating corruption. However, the move also highlights the proximity of the scandal to the president himself, as the main suspect in the probe is a former business associate of Zelenskiy.

In a public statement, Zelenskiy said he accepted Yermak’s resignation to move past the scandal and present a united front in the ongoing war and peace negotiations. Ukraine continues to face pressure from the US to consider peace proposals involving territorial concessions and limitations on its armed forces, while Russian President Vladimir Putin has sought to question Zelenskiy’s legitimacy. The scandal also comes as Ukraine tries to demonstrate progress in tackling corruption, a key requirement for joining the European Union.