On Nov. 28, Andriy Yermak resigned as chief of staff to Ukrainian President Volodymyr Zelensky, hours after anti-corruption investigators raided his home. The timing could not be worse.

Yermak wasn’t just another presidential aide – he was Ukraine’s second most powerful figure, and he was leading Ukraine’s delegation in critical peace talks with the United States when the scandal broke. His departure creates a power vacuum at the center of Ukrainian governance at perhaps the most dangerous moment since Russia’s full-scale invasion began.

Yermak had built something unprecedented in Ukrainian politics: a parallel government that touched every lever of power. After replacing the ebullient Andriy Bohdan as chief of staff in February 2020, he consolidated even more authority than his predecessor, extending his influence across parliament, the cabinet, and state institutions. Ministers understood that access to Zelensky – their political survival – depended on maintaining good relations with Yermak.

Major decisions on military strategy, economic policy, and diplomatic initiatives all flowed through his office. He had become what one European official privately called “Zelensky’s man,” or rather his gray cardinal – the gatekeeper everyone had to deal with, whether they liked it or not.

The catalyst for his fall was the Energoatom scandal, the largest corruption investigation of Zelensky’s presidency. Prosecutors allege that approximately $100 million was systematically embezzled from Ukraine’s state nuclear power operator – the company that provides around half the country’s electricity.

The alleged ringleader is Timur Mindich, a close associate of Zelensky himself. While Russia has spent nearly three years bombing Ukrainian power plants, someone was allegedly stealing funds that could have repaired infrastructure or supported the war effort. For a president who came to power in 2019 on an anti-corruption platform, it’s a devastating blow.

But here’s the thing: The very fact that anti-corruption investigators could raid the president’s closest advisor’s home and force his resignation shows Ukraine’s reformed institutions are actually working.

The National Anti-Corruption Bureau of Ukraine (NABU) and Specialized Anti-Corruption Prosecutor’s Office (SAPO), created after the 2014 Euromaidan Revolution, have proven they can pursue cases against even the most powerful officials. For years, skeptics questioned whether these bodies would be captured by political interests. The Yermak case provides a powerful answer.

For Ukraine’s international ambitions, this matters enormously. The EU has made clear that Ukraine must meet high governance standards to qualify for membership. Anti-corruption reforms aren’t optional – they’re prerequisites. The US Congress, which must regularly approve military aid, has cited corruption concerns as a reason for hesitation.

Demonstrating that Ukraine will investigate and punish high-level corruption – even when it affects the president’s inner circle – addresses these concerns directly.

But Yermak’s departure also creates immediate dangers. His hyper-centralized power structure, while problematic for democracy, provided a form of stability during wartime. He mediated between competing factions, managed tensions between civilian and military leadership, and held together a complex web of relationships.

As Ukrainian political observers are already saying, his removal represents “tectonic shifts.” The ground beneath Ukrainian politics is moving. Who will coordinate between the presidential administration and parliament? Who will manage relationships between security agencies? Ukraine’s leadership must now improvise at a moment when clarity is essential.

The diplomatic implications are even more urgent. Yermak had become Ukraine’s primary interlocutor with the West, particularly Washington, and was allowed to act as de facto foreign minister. He led the Ukrainian delegation in Geneva peace talks, serving as the principal channel between Kyiv and the US on the most sensitive issues of war and peace.

Although reputedly not popular in Washington, Western officials had come to see him as the person who could speak authoritatively for Zelensky and navigate Ukraine’s complex internal politics.

His resignation comes as Ukraine faces intense pressure to accept a negotiated settlement with Russia. The Trump administration has proposed a peace plan that has largely reflected Russian demands, including territorial concessions and limitations on Ukraine’s security arrangements. Some Western partners are experiencing “Ukraine fatigue” – their publics weary of the war’s economic costs. There’s a growing sense in some capitals that the war has reached a stalemate that will persist while Trump and Putin both stall for time.

There’s also a credibility problem. When a country’s chief negotiator resigns amid a corruption scandal, it raises questions about the government’s stability. It provides ammunition to skeptics who argue Ukraine isn’t ready for EU or NATO membership. It may embolden Russia to take a harder line, calculating that Ukrainian political instability creates opportunities for exploitation.

The pressure for Yermak’s resignation came not just from opposition parties but from within Zelensky’s own coalition. Members of parliament who had initially supported the president began expressing concerns about Yermak’s dominance, worried that concentrating so much authority in one individual created a single point of failure. That internal dissent persisted and ultimately contributed to Yermak’s departure speaks to the resilience of Ukraine’s democratic culture, even during wartime.

President Zelensky initially refused to dismiss Yermak despite mounting pressure, revealing the depth of their relationship. That he ultimately accepted the resignation demonstrates that even the president’s considerable wartime authority has limits.

Ukraine now faces a test: Can it show that Yermak’s resignation represents accountability rather than chaos? That means a transparent investigation into the Energoatom case, clear communication about governance reforms, and the appointment of a credible figure to fill the diplomatic void – all while fighting a brutal war against a much larger adversary.

What’s at stake here goes beyond one scandal or one resignation. Ukraine is fighting for its existence as an independent, democratic nation. That fight is happening on battlefields, in Kyiv’s government offices, in Washington and European capitals, in courtrooms. Yermak’s resignation marks a critical moment in all of them.

On the foreign scene, Yermak’s successor will need to establish credibility with both Ukrainian and international audiences. Fortunately, Ukraine has a number of potential candidates for this role, experienced diplomats who have been sidelined during Yermak’s “rule.”

What Ukraine builds in the aftermath will matter more than one man’s fall. If the country emerges with stronger institutions and a cleaner government, this could be remembered as a painful but necessary step forward. If it triggers instability that Russia exploits, the consequences could be severe.

The Ukrainian people, who have sacrificed so much, deserve leaders who understand what’s required. The world, which has invested heavily in Ukraine’s success, needs them to succeed too.

But, undoubtedly, Zelensky now finds himself even lonelier and more beleaguered. But perhaps lessons may have been learnt, and this is an opportunity for a new approach.