Has Russia invaded Ukraine?

It's probably fair to say that last fall, when protesters thronged a historic square in Kiev, few imagined that the situation in Ukraine would escalate to this level less than a year later. 

The map has been redrawn by Russia’s annexation of the Crimean Peninsula, and in eastern Ukraine pro-Russian rebels are being aided and fortified by Moscow. Now, according to newly released satellite images made public by NATO, Russian troops in Russian military vehicles have rolled over the border between the two countries. 

Ukraine’s new President Petro Poroshenko seems to have upped the ante by using the Ukrainian military to resist the stealth seizure of his country’s eastern provinces. The situation may be escalating into something that gives pundits and policymakers the willies: war in Europe.

Who are the men coming to the aid of separatists in eastern Ukraine?

What is Moscow’s goal?

What is the West prepared to do in response to Russia’s actions?

We discussed these questions and more with a panel of experts on this edition of “Inside Story.”