Geographically, Ukraine is midway between the liberal democracies of the European Union and the authoritarian oligarchies of the former Soviet Union. It's also in-between economically and politically and, in recent weeks, tensions have led to increasingly violent protests. Over the weekend elected President Victor Yanukovich made strategic concessions, but they weren't good enough for angry demonstrators, who are calling on him to step down. In Kiev and other cities around the country, they've occupied government buildings, and police seem unable to enforce new laws designed to crackdown on dissenters. How long can it last? Is there a risk of civil war? What are the stakes for Russia's Vladimir Putin? What about the US and the consequences for the global economy?