By sending troops across Ukraine’s borders, Vladimir Putin, Russia’s president, aims to weaken and destabilise the struggling new government in Kiev and coerce it to stay within Moscow’s orbit. Thus begins the opening act of a dangerous crisis that risks dividing Ukraine along ethnic and geographic lines. It is the most serious threat to Europe’s security since the end of the cold war.
Burns, Nicholas. "The US and EU have Options to Outmaneuver Russia." Financial Times, March 2, 2014.