RFE/RL's Ukrainian Service correspondents Olena Matusova, Inna Kuznetsova, and Vitaliy Yeremitsa contributed to this report from Kyiv. RFE/RL Russian Service correspondent Mikhail Sokolov contributed from Moscow

"Ukraine at the Rubicon." "Kyiv at a geopolitical crossroads." "The battle for Ukraine."The headlines have been dire and the expectations high as the clock ticks down to the European Union's Eastern Partnership summit in Vilnius at the end of this month.With less than two weeks to go, the main potential achievement of that summit -- the signing of an Association Agreement between Ukraine and the EU that has been more than five years in the works -- remains very much up in the air.For months, the government of Ukrainian President Viktor Yanukovych seemed to be building momentum in its European-integration drive. It passed key reform legislation and indicated openness to releasing from prison former Prime Minister Yulia Tymoshenko, whom the EU views as a victim of selective justice.But pressure from Moscow -- which wants Kyiv instead to join its customs union -- has grown as the proposed signing become increasingly imminent. Yanukovych has held at least three secretive meetings with Russian President Vladimir Putin in the last two weeks, and in their wake the Ukrainian leader's enthusiasm for Euro-integration seems to be waning."The EU has been right to say that there is at the moment no Plan B because momentum is all-important -- and if there isn't a signature in Vilnius, that momentum will clearly be lost," notes Andrew Wilson, a senior policy fellow at the European Council on Foreign Relations. "And 2014 will be a year of preparation for the [Ukrainian] presidential election in early 2015."Former Polish President and EU envoy to Ukraine Aleksander Kwasniewski told journalists on November 14 that failure to sign on the dotted line in Vilnius could mean "the postponing of the agreement for an."Analysts say Kyiv's decision is crucial for both Brussels and Moscow. The EU, worn down by enlargement fatigue and the effects of the global financial crisis, needs to show that it has the attraction and will to pursue its broad, post-Berlin Wall mission of "a Europe whole and free," Wilson says.He adds that Ukraine is also essential to Putin's flagship project -- the Eurasian Union. "It is key to Putin and the key project of his term -- growing the customs union into the Eurasian Union," Wilson says. "It is also key to Putin and to Putin's friends -- the kind of private business interests that Russia wants to promote in Ukraine.Without Ukraine, Putin's Eurasian Union would become a decidedly Asian project, and Ukraine's economy -- although much smaller than Russia's -- is the only one in the former Soviet Union capable of imbuing the Eurasian Union with a semblance of balance.So Moscow will not relent in its efforts to prevent Ukraine from integrating with the European Union, even if Kyiv proceeds with the Association Agreement, says former Russian Deputy Prime Minister and opposition politician Boris Nemtsov."Signing a partnership agreement with Europe is a difficult decision that will be very painful for the Ukrainian economy during the first years. But sooner or later they will have to pass through these difficulties, and I think it is better to do it sooner rather than later," Nemtsov says."It is obvious that Putin will impose sanctions against Ukrainian goods. There will be trade wars, that is obvious. It is impossible to tell what will happen with natural gas," he adds. "No one says it will be easy. But overcoming these difficulties is unavoidable."Political scientist Andreas Umland of the Kyiv-Mohyla Academy wrote recently that, "Should Moscow use its considerable leverage to the full, the Ukrainian economy would be unable to withstand, and could go into a free-fall."And Yanukovych is skeptical that European institutions have the will to prop things up.The stealthy Putin-Yanukovych meetings recall a closed-door session the Kremlin leader had with Armenian President Serzh Sarkisian on September 3, after which Sarkisian surprisingly announced that his country would join the Customs Union of Belarus, Kazakhstan and Russia, despite being on the verge of initialing a long-negotiated Association Agreement in Vilnius.Tellingly, Ukrainian Prime Minister Mykola Azarov said on November 13 that "the normalization of relations with Russia is question No. 1 of our national policy." He noted that a decrease in exports to Russia by more than one-quarter as a result of a Moscow-imposed customs slowdown had hit the country's economy hard.Moreover, Ukraine's parliament has failed repeatedly -- most recently on November 13 -- to pass the legislation needed to release Tymoshenko, and Yanukovych has been unwilling to free his longtime political rival by executive fiat.Pro-Russian forces in Ukraine are also mobilizing to sway public opinion. Former lawmaker Viktor Medvedchuk -- who has close personal ties to Putin -- has formed an organization called Ukrainian Choice that is posting billboards in Ukraine claiming that association with the EU will mean the legalization of same-sex marriage.This is a salient issue in Ukraine. The same October poll found that 48 percent of Ukrainians oppose increased tolerance toward homosexuals and other sexual minorities.But Moscow isn't the only formidable force turning up the pressure on Yanukovych. Many of Ukraine's powerful oligarchsby Kremlin-friendly business interests and are therefore pushing hard for Kyiv to move toward Europe."The Ukrainians -- if you take the situation to its logical conclusion -- could end up as hired managers of those enterprises that are competitive with Russian ones. This future, of course, does not satisfy the absolute majority of the Ukrainian elite that currently owns these enterprises. There aren't that many of them, but they are the drivers of the Ukrainian economy," explains Kirill Koktysh, a professor at the Moscow State Institute of International Relations (MGIMO)."So, for this reason, naturally, they are seeking protection from the European Union from such a swallowing-up. It isn't a drive to make things better but essentially just to protect themselves from Russia."The wrangling is being played out against the background of Ukraine's 2015 presidential election, which promises to be highly divisive.Vitali Klitschko, leader of the opposition Udar party, told RFE/RL's Ukrainian Service that he was already gearing up for the vote. "There is a Plan B. Our next fight is the fight for the office of the president," he said. "And the president should implement the European rules of life."Klitschko is urging Ukrainians to attend a November 24 rally in Kyiv that will be a multiparty show of support for Ukraine's pro-European course. "The flags could be Ukrainian; these flags could be European, because Ukraine is Europe," he said. "This is not a party meeting, not an action of a party or a certain political force. It is the wish of all Ukrainians, regardless of their political views, to live in a European country."Public support for a pro-EU course is currently strong. According to a poll conducted in October, 45 percent of Ukrainians support the Association Agreement, while only 14 percent want to join the Russia-led customs union. Nearly half of the supporters of Yanukovych's ruling Party of Regions support the EU agreement, while opposition voters support it in even greater numbers.And in addition to the celebrity that being the reigning world heavyweight boxing champion brings, a presidential bid by Klitschko -- or another pro-European candidate -- could also count on some influential financial backers.Ukraine's leading oligarchs -- those who are spooked by the prospect of being muscled aside by Russian rivals -- seem poised to line up behind a pro-European candidate, if Yanukovych balks at signing the agreement."The entire oligarchy understands they have to play by rules. The time is coming when rules are needed because without rules, without institutional stability, without institutional transparency, the company loses its value," says Vadym Karasev, the director of the Global Strategies Institute in Kyiv."The value of the country will fall. As much as the oligarchy has invested in Ukraine, in its development --, creating media groups -- all that could collapse into dust."