The Russian blockade began at midnight on Jan. 29. At factories and warehouses across neighboring Ukraine, truckers had picked up their regular haul of cargo that afternoon and made their way to the eastern border. If their radios were tuned to the news as they drove along the icy highways, they would have heard some alarming bulletins. Ukraine’s Prime Minister and his entire cabinet had resigned that morning, forced out by the revolution that has gripped the nation for two months. But the truckers only felt the impact of the crisis when they reached the border with Russia.

On orders from Moscow, customs agents forced the Ukrainian trucks to stop, unload their cargo and wait in the freezing cold while the cargo was inspected piece by piece. “Most of them are still standing there, running their engines to stay warm,” says Yuri Kuchinsky, vice president of the national truckers’ association of Ukraine, nearly three days after the blockade began. “This is not the way brotherly nations behave.”

But brotherly or not, this was a signal to Ukraine’s President not to forget where his loyalties should lie. As the uprising has forced him to grant more and more concessions to the protestors, officials in Moscow have begun to fear, with good reason, that their fragile hold over Ukraine is slipping, and they have deployed various forms of pressure to reclaim and preserve their control. Apart from choking off the flow of goods at the border, Russia has frozen a financial lifeline to Ukraine worth $15 billion and launched an information war blaming the United States for funding the revolution. Kremlin officials, meanwhile, have started calling on Viktor Yanukovych, the embattled President of Ukraine, to use force against the revolutionaries. Taken together, these efforts seem to be working. At the very least, they have already urged Yanukovych to stop granting concessions to the protestors and to start moving toward a crackdown.

Still, the crisis in Kiev marks a dramatic reversal of fortunes for Russia. Only two months ago, it seemed as though President Vladimir Putin had finally won his decade-old struggle to pull Ukraine away from the West. The apparently decisive victory for him came on Nov. 28, when Ukraine missed its last chance to sign an historic integration deal with the European Union during a summit in Lithuania. That day in Ukraine’s capital, Kiev, thousands of protestors gathered to demand that Yanukovych take the deal. But under immense economic pressure from Russia – including threats of a blockade of Ukrainian goods – he refused, choosing instead to pursue closer ties with Moscow.

Putin and his allies celebrated that day at an awards ceremony inside Moscow’s main cathedral. One of the top prizes – “Person of the Year” – went to the Kremlin official who has overseen the struggle for Ukraine from behind the scenes. Sergei Glazev, one of Putin’s top advisers, was given the award for achieving “the return of Ukraine to a united economic space with Russia,” according to his official website. But he did not have much time to sit on his laurels, as the protests in Kiev turned violent the following night.

At around 4:00 a.m. on Nov. 30, riot police armed with batons, tear gas and stun grenades descended on Independence Square, where a few hundred protestors, most of them students, were holding an all-night vigil to call for integration with the E.U. Dozens of them were severely beaten in the clashes, which lasted well into the following day. “That was the turning point,” recalls a senior Ukrainian official, who spoke on condition of anonymity. “After they beat up those kids, their parents came, and then their parents’ friends came. It was an irreversible mistake.”

In the weeks that followed, the peaceful protests devolved into a ferocious cycle of violence between protestors and police. At least four people have been killed and nearly 700 hospitalized in Kiev alone, according to the local health ministry, while protestors armed with clubs and Molotov cocktails have seized government buildings across the country. Throughout these clashes, Russia watched from the sidelines, publicly insisting that the uprising was a domestic matter that Ukraine must deal with on its own. But that changed on Jan. 29, when Yanukovych accepted the resignation of his entire government in a desperate bid to appease the protestors.

Andrei Klimov, a Russian diplomat involved in talks with the E.U. over Ukraine, calls it a search for clarity. “We need to know who we are dealing with in Ukraine,” he tells TIME. At the end of last year, Ukraine’s Prime Minister had personally negotiated the country’s turn towards Moscow, including the terms of a $15 billion loan that Putin granted to Ukraine in December. That loan was not only an economic lifeline but a reward for the renewed alliance. But with the Prime Minister and his cabinet gone, “who is in charge of what? Who will answer for what?” Klimov asks. “Until we know that, of course we are concerned about the status of our agreements.”

That concern has led Russia to take some drastic measures. On Jan. 30, the day after Ukraine’s government resigned, Putin told his cabinet to stop disbursing the emergency loan to Ukraine at least until Russia can assess the views of Ukraine’s future Prime Minister. The impact on Ukraine’s economy was instant. Without the access to the loan, Ukraine faced imminent bankruptcy, and international ratings agencies further downgraded its national debt to junk status. Investors fled, and the value of the currency plummeted.

The next day, Glazev, the Putin adviser who answers for Ukraine, called on Yanukovych to crush the rebellion at once. “The President has a choice,” Glazev said in a rare interview with the corporate journal of Gazprom, Russia’s state gas monopoly. “Either he defends Ukrainian statehood and puts down the insurrection…or he risks losing power, in which case Ukraine faces growing chaos and internal conflict with no escape to be seen.”

Glazev then trotted out a trusty Russian tactic, the same one Putin used when putting down a revolt in his own capital two years ago – he blamed the conniving West. “The factor of foreign influence is the number one factor we have to consider today,” he said. “We underestimated the force of its surge, underestimated American geopolitics, whose goal in the post-Soviet space follows the British model of 200 years ago – divide and conquer.” As evidence, he claimed that Ukraine’s money changers suddenly have lots of newly-minted American dollars, which the U.S. is allegedly using to bankroll the revolt. “Kiev is full of them,” he declared. “While Moscow doesn’t have this new type of dollar.”

In the past few weeks, the Kremlin’s television channels have flooded the airwaves in Ukraine with such theories. Through satellite dishes, they reach millions of people in the eastern and southern parts of Ukraine, where locals speak Russian as their native language and prefer to watch Russian TV. “Remember, this is Yanukovych’s base of support,” says the Ukrainian official close to his government. “And they are getting doused with this propaganda every day. Of course this has a huge impact on how they see the crisis.”

That has also been the electorate hardest hit by the blockade of Ukrainian goods. Eastern Ukraine is the country’s industrial heartland, studded with factories that provide jobs to millions. Kuchinsky, from the truckers’ association, says Russian customs agents have been specifically targeting cargo manufactured in Ukraine. “The stuff made in China sails right right through,” he says. “But if it’s made in our factories, even if it’s only a bunch of bolts, they give it the full treatment, unloading, piecemeal inspection, the works.”

In just a few days, the blockade has paralyzed the country’s cargo carriers, Kuchinsky says, and if it lasts long enough, it will force factories to cease production and put workers on leave. From Russia’s point of view, that will not only send a powerful warning to the President in Kiev, but will also push his core electorate to demand an end to the uprising – to do whatever it takes to make Russia open the border. Speaking from Moscow, Klimov, the diplomat, insists the blockade has no political motives. “When unwashed men with clubs occupy government ministries and doing God knows what, of course you are going to start checking the goods coming out of that country more carefully,” he says. “Any western country would do the same.”

But more broadly, Klimov admits that Russia is using every available tool “to get it across to the people of Ukraine which path is more natural for them as a whole.” The problem, as ever, is Ukraine’s internal divide. Even if some of the eastern and southern provinces are eager for a union with Russia, or at least prepared to live with one, the western half of the country is intent on integration with the West. They are the ones dominating the uprising, and if they win out in this revolution, Russia can forget about civil relations with Ukraine, let alone a brotherly partnership.

On the occupied squares of Kiev, Russia has already become the enemy. The leaders of the uprising released a poster on Saturday showing a Ukrainian girl with a black eye and swollen lip. “Russia, hands off Ukraine!” the caption reads. “No to brutal torture and murder of political opponents in Ukraine! No to Russian encroachment on Ukrainian sovereignty!” Clearly, in the minds of many protestors, these demands have become intertwined, and Klimov admits that this is a major problem for Russia. “Nobody knows where it will lead and how it will end,” he says. So while Russia still has a chance, it is scrambling to regain control.

At the very least, it has gotten the President’s attention. Since the resignation of his government and the start of the Russian blockade, he has cut off negotiations with the protest leaders, rejecting their latest appeal for an unconditional amnesty of demonstrators. His primary option now is a crackdown – much like the one that Putin’s adviser has told him to impose.

Contact us at letters@time.com.