On Tuesday night, police in Ukraine began to storm the protest camp in the center of the capital, Kiev, using water canons, tear gas, truncheons and rubber bullets. In the course of the day, which was the most violent in Ukraine’s post-Soviet history, 20 demonstrators were killed reportedly alongside seven members of the security forces. But the dilemma now facing the state and the police is far more complicated than clearing a city square filled with thousands of people. They also have to dislodge the intricate community of revolutionaries that has taken root there over the past three months. In the space of roughly ten city blocks, the uprising has established a city within a city, a barricaded fortress with its own police force, its own economy, its own hospitals, a parliament, a cathedral, even a library and, most importantly, its own political ideals. Those cannot be chased away with rubber bullets.

The revolutionary fortress, which is known as the Maidan (the word for “city square”), also had its own command structure, independent of the political leaders of the revolution who have been trying in vain to negotiate an end to the crisis. One of the three overseers of the Maidan, known as commandants, is Stepan Kubiv, a lawmaker in the national parliament for the pro-Western Fatherland party. On Tuesday, as the government troops surrounded the Maidan and tire fires raged along its perimeter, he got on the stage in the center of the square to explain what was at stake. “Stand up, Ukraine!” Kubiv shouted into the microphone. “Today the fate of our children and grandchildren is decided. The fate of all of us!” Then, in a hint at the bloodshed likely to ensue by morning, he told the armed men guarding what was left of the barricades, “Death to the enemies!”

TIME had met with Kubiv only two weeks earlier, at the revolutionary headquarters built inside the occupied House of Trade Unions building, which lies at the edge of the square. At the time, Russia had just begun to exert intense pressure on President Viktor Yanukovych to crush the pro-European rebellion and reaffirm his alliance with Moscow, and that pressure seems to have persisted. On Feb. 7, at the opening ceremony of the Winter Olympics in Sochi, Yanukovych met with his Russian counterpart, Vladimir Putin, to discuss the crisis, and although the results of those talks were not made public, the Ukrainian leader has since ceased his earlier policy of appeasing the protesters and has begun preparing for a stand-off.

So have protest leaders like Kubiv, who has been digging in for an almost indefinite struggle. “I am not a politician here,” he explained at the end of January. “I am an administrator, like the mayor of a city.” His job, he said, was to ensure that the Maidan community not only survived but that it remained resilient enough to withstand an assault like the one that began on Tuesday night. “We are prepared to stay here as long as needed,” he said calmly, his hands folded over his round stomach. “Two years. Three years. As long as it takes for our demands to be met.”

He then rattled off the revolution’s five demands, noting the ones that the government had already granted as concessions to the revolutionaries. First, fire the Prime Minister and the entire cabinet. That was granted on Jan. 28. Second, repeal the anti-protest laws passed in mid-January, just before the state made its first bloody attempt to clear the square. That attempt failed, and the laws were soon repealed. Third, provide a legal amnesty to all protesters. That was also granted, though with some preconditions. Fourth, pass constitutional reforms to strip the President of many of his powers. The parliament has been in talks to achieve that for weeks, and they were getting close. But then came the fifth demand: “Change society,” Kubiv said. “Turn Ukraine into a European country.”

How, exactly, is that? In November, the revolution began when President Yanukovych refused to sign an integration deal with the E.U., choosing instead to pursue closer ties with Moscow. Did Kubiv mean that Yanukovych must make another U-turn and take the E.U. deal? “No,” he said. “That’s not enough.” The revolutionaries need to see more than that. They want concrete progress toward the creation of a society with rule of law, no corruption, upward mobility based on merit rather than connections, freedom of the press – all of the values they associate with Europe. “We want all of Ukraine to have the values that we have built here on the Maidan,” Kubiv said.

In some ways, those values have taken root inside the fortress. Disregarding all the soot and smoke from the barrel fires rimming the barricades, the masked and somber revolutionary guards, the constant speechmaking from the stage, the cold and the uncertain future, the Maidan felt to many like a more equitable society than the one on the other side of the barricades. Young people came from all over the country and volunteered to help the Maidan’s day to day life. They were given responsibilities that made them feel a sense of purpose and potential, something their universities and day jobs had not provided in Ukraine.

Andrei Oleynik and Danil Tsvok, both 23, had come from the city of Lviv, in western Ukraine, where they are students at a technical college. At the Maidan, Kubiv put them in charge of securing supplies of firewood to fight the freezing winter cold – 200 cubic meters of it per day. It became a daily adventure. Not only did they have to get the firewood from wholesalers sympathetic to the revolution on the outskirts of town, but they had to haul it in trucks to the Maidan in the center, navigating the police checkpoints that often stopped, detained and interrogated them.

And why were they doing this? Didn’t they have final exams to think about? Job prospects and girlfriends? “It’s fun to be a part of it,” says Tsvok beaming. “A new social order is taking shape here, a new model for society.” His friend took a slightly longer view of the revolution. “It’s not even about us or our future,” says Oleynik. “We know we may not be able make Ukraine like Europe in just a few years.” The point of the uprising, Tsvok added, is to make a break from Russia and its values, which he saw as fundamentally corrupt, lacking in basic freedoms and, most importantly, devoid of opportunities for the young.

But how would they even know when they’ve succeeded? When would they be satisfied enough with the results of the revolution to leave the Maidan behind? Is it even possible for the state to meet Kubiv’s final and most abstract demand? “It is possible,” Kubiv says. “And we are prepared to wait.”

The government, however, no longer was. In recent weeks, the President has begun to feel that he has granted enough concessions. “We already have our backs against the wall,” Nestor Shufrich, a prominent lawmaker from Ukraine’s ruling party, told TIME in late January, soon after the amnesty was granted and the Prime Minister and his cabinet resigned. “We cannot retreat another step.”

It then took another three weeks of rancorous negotiations for the patience on both sides to run out. Finally, on Tuesday morning, the protesters marched out of the Maidan and surrounded the parliament building, demanding that the chamber vote through constitutional reforms immediately. The police, fearing that the Maidan would spread even deeper into the government quarter of the city, began to fight them back with truncheons. Demonstrations meanwhile intensified across the country. In the western Ukrainian city of Ivano-Frankiyvsk, for instance, protesters laid siege on Tuesday night to the headquarters of the SBU secret police, the successor agency to the Soviet KGB.

By nightfall in Kiev, the riot troops had pushed the protesters back toward the Maidan, and they decided to continue while they had the momentum. After surrounding the square, they tore down its first line of barricades and began to storm the rest of it. Stones and Molotov cocktails flew at them from the crowd, but unlike the clashes in January, the troops were either disciplined or furious enough to withstand the barrage, standing their ground even as the flames burned beneath their feet.

The President, through one of his lawmakers, then issued an ultimatum: He would meet with the opposition leaders to continue talks on Wednesday at noon, but only if the protesters cleared their beloved square once and for all. The Maidan refused, and the siege looked set to continue through the night. But even if the troops succeed in clearing the square of the tents – an effort that is almost sure to cause more bloodshed – they will not dislodge the principles the Maidan has attempted to create inside its fortress of ice and burning tires. In one form or another, those are almost sure to haunt Ukraine until the state accepts Kubiv’s fifth, era-defining demand.

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