People gather outside a court building to prevent the release of the head of Ukraine’s tax and customs service, Roman Nasirov, in Kiev. (Valentyn Ogirenko/Reuters)

Maxim Eristavi is a nonresident research fellow with the Atlantic Council and co-founder of Hromadske International, an independent news outlet, based in Kiev.

It’s 3 o’clock on Monday morning, and I’m standing in a huge crowd behind a courthouse in downtown Kiev. Dozens of cars are blocking the streets, and the low roar of generators competes with music blasting from loudspeakers. I look around and see a mixed crowd: I recognize the faces of leftists, liberals, conservatives and people from the far right. I see reformist politicians, independent journalists and prominent anti-corruption activists. LGBT campaigners and prominent homophobes are standing shoulder to shoulder. All feuds have been suspended, because what’s happening inside the court building, which is now completely surrounded by protesters, is crucial to the future of Ukraine.

I’m experiencing a powerful sense of deja vu — as if I were reliving the culmination of the Maidan Revolution three years ago. The fate of the revolution is now being decided in that courtroom.

Currently being held inside the building is the head of the Ukrainian Fiscal Service, Roman Nasirov. He’s at the center of the biggest anti-corruption case in the country’s history. Well, to be honest, the only major one to date.

Nasirov, who is Ukraine’s top tax official, stands accused of fraud and embezzlement (to the tune of $74 million). Yet since his arrest on March 2, the judges assigned to the case have been conspicuously dragging their feet in pretrial hearings. Tensions spiked when the judges failed to meet deadlines, almost allowing Nasirov to walk without facing justice. That’s when the anti-corruption protesters moved in, blockading the court so that Nasirov wouldn’t be able to leave.

But you don’t need to know all the details in order to understand why Nasirov’s arrest is turning out to be the most important development in Ukraine since the 2014 revolution.

First, Nasirov is the highest-ranking government official to face the real prospect of jail time over corruption charges in a country that is notorious for pervasive yet unpunished graft. Second, he’s a key aide to President Petro Poroshenko — meaning that this is the first time any member of the presidential entourage has faced legal responsibility over alleged malfeasance. For millions of Ukrainians, seeing such a powerful official as a defendant in court is something of a catharsis: It has never happened before. Third, this is a do-or-die moment for the newly created National Anti-Corruption Bureau, which put the case together.

Even more important, the arrest of the tax chief is a long-delayed moment of truth for the Maidan Revolution, which took place in February 2014. The uprising has failed to live up fully to its promise. Even before his arrest, Nasirov, 38, embodied the country’s rent-seeking culture: He’s the kind of man who thrives at the places where bureaucracy and oligarchic interests intersect. He made his career in investment management (a delicate task in a country as corrupt as Ukraine). Since there are almost no clear dividing lines between powerful business interests and the government, it’s only natural for people like Nasirov to become government officials. Before the 2014 revolution, he worked with ex-president Viktor Yanukovych (now a fugitive in Russia); after it he got a job with President Poroshenko’s team, steadily pushing his way to the top of the official hierarchy.

If you’re a foreigner, you might find it odd that Ukraine’s post-revolutionary leaders, who call themselves “reformers,” would hand a key government post to someone from the old regime. In fact, this goes straight to the question of why reform efforts have virtually ground to a halt. To use a phrase currently in vogue in the United States, no one has managed “to drain the swamp.” In post-revolutionary elections, voters chose a record number of reformers to run the country — but in some cases, whether deluded or simply resigned, they also picked figures closely associated with the established business and political elite. The latter managed to camouflage themselves as agents of change.

And it’s entirely possible that some of them, like Poroshenko, really wanted to transform the country. Yet they failed to transcend the inherited rules of the game — perhaps because they were ultimately creatures of the old system. They stubbornly persisted in running things the way they have been run for most of the past 25 years: through a small circle of the most powerful businessmen, who combine their economic leverage with political power. They just don’t know how to succeed in any other way.

That’s where people like Nasirov are indispensable. That’s why Poroshenko’s team can’t imagine itself without people like him. And that’s exactly why every single (authentic) reformer in post-Maidan Ukraine hates him.

Under Nasirov’s watch, the Fiscal Service of Ukraine has been consistently rated by businessmen as the most corrupt branch of government. He drew the ire of reformers by quashing an ambitious campaign to restructure the notoriously corrupt customs service. He antagonized civil society by allegedly failing to declare his ample holdings of British real estate.

Nasirov, in short, is a living symbol of the distortions of the current system. And that’s why the system is fighting so hard for him in that Kiev court, where just two anti-corruption detectives are facing nine lawyers defending Nasirov. Several of them have extensive records of working for oligarchs and high-profile officials.

The ongoing courtroom drama in Ukraine exposes two other disturbing tendencies. First, foreign diplomats and journalists don’t seem to be grasping the full import of what’s happening now — just as they failed to do back in 2014, when it took outside observers weeks to comprehend the magnitude of the revolution.

Now, it would seem, we are back to square one. Days into the most important development in Ukraine in the past three years, the foreign media are missing the story. It wasn’t that long ago that Western embassies were bringing their leverage to bear in every key crisis; this time around the diplomatic community shows little inclination to get involved. The recent change of leadership in Washington has left many foreign diplomats on the ground demoralized and reluctant to engage.

Second, there is a good chance that Ukraine’s biggest anti-corruption case will fall apart in court. As any reformer will tell you, the justice system in this country is still a bulwark for corrupt elites. It is simply not designed to deliver justice.

There are good reasons that Ukraine is a country of deeply ingrained cynicism. Yet the remarkable surge of public interest and activism that we’ve witnessed over the past few days shows that civil society and public anger are still a powerful and unpredictable force here. And that, at least, offers grounds for hope.