On Wednesday, as public demonstrations against him mounted, Romanian Prime Minister Victor Ponta resigned. But Romania's protesters aren't finished: That evening, at least 10,000 took to the streets of Bucharest, the capital. Yelling slogans like, "Don't be afraid, the country is rising up!" they demanded political reforms and called for elections to take place earlier than December 2016, when they're currently scheduled.

Clearly, Romanians are furious with their government. The primary reason for the protests, and for why the resignation wasn't enough to quell the furor, can be summed up in one word: corruption.

This began with a nightclub fire

The current round of protests grew out of an uncommon sort of political catalyst: a fire at a nightclub.

Last Friday, about 400 people showed up to Colectiv, in Bucharest, to see the band Goodbye to Gravity perform. The band set off pyrotechnics during their show, but the club wasn't up to code. A spark set off some of the insulation, which was flammable. As the fire spread, people tried to get out through the club's two doors — but only one of them would open initially. Thirty-two people died, and about 180 were injured.

Romanians didn't see this as a one-off incident; they saw it as a direct result of deep, systemic corruption in the Romanian government — the kind of corruption that would allow nightclub owners to operate without inspectors noticing their improper safety precautions.

Prime Minister Ponta was already, at the time, on trial on forgery, money laundering, and tax evasion charges. With the fire as well, he came to symbolize everything that was wrong with the Romanian political status quo.

On Monday, three of the owners of the nightclub were arrested for failing to keep their club up to code — but that didn't satisfy Romanians. Tuesday night, 20,000 demonstrators turned out in Bucharest. "Corruption kills" was a popular slogan.

That was the final straw for Ponta, who recently survived a no confidence vote that almost ousted him in September. He resigned on Wednesday, along with the interior minister and the Bucharest city official in charge of the area where the fire happened.

The bigger context: widespread, systemic corruption

In Transparency International's latest Corruption Perceptions Index, Romania is tied for the most corrupt country in the European Union, alongside Greece, Italy, and Bulgaria.

Politicians in Romania can be breathtakingly overt about enabling corruption. In December 2013, for example, Romania's parliament simply waited until late at night, when all the journalists were gone, to hold a vote repealing all of Romania's conflict of interest laws for politicians.

Alina Mungiu-Pippidi, a professor at the Hertie School of Governance in Berlin, estimates that this corruption costs up to €323 billion ($351 billion) annually in stolen tax collections alone, a huge loss for the economy.

"As the most corrupt country in EU-28 Romania loses a tremendous amount of money," she writes. "Even though taxation in Romania is roughly similar to the European average, the actual collection rate is consistently between 29–31 percent of GDP, a full 10–15% of GDP lower than in most Central and Eastern European countries."

Romania has been trying to get the problem under control for years. In 2003, the government created a specialized anti-corruption task force called the DNA to investigate high-level corruption. It's quite popular with the public — in one poll, 60 percent of Romanians said they trust the DNA, while only 11 percent said the same about parliament. But the investigators are swamped.

Last year alone, the Guardian reports, "the agency successfully prosecuted 24 mayors, five MPs, two ex-ministers and a former prime minister, not to mention more than 1,000 other individuals, including judges and prosecutors, with a conviction rate above 90%."

Despite all this work, the DNA hasn't come close to rooting out the country's institutionalized corruption. "While the country’s judicial anti-corruption [efforts] accelerated" between 2010 and 2015, Mungiu-Pippidi writes, "the population only complained in surveys that corruption is getting worse and is becoming more systematic."

That's why the protestors weren't satisfied with Ponta's trial and resignation: They blame the corrupt system, not merely one man, for their country's woes — nightclub fire included. The struggle to clean up Romania is very far from over.