Are Russia's oligarchs the key to stopping Putin?

<div>Russian forces are attempting to take Kiev, the capital of Ukraine. Ben Wallace, the defence secretary, said he would be spending the day trying to convince European allies like Germany and Italy, who are reluctant to put too harsh sanctions on Russia, to ban them from the Swift payments system. How else can the West put Putin under pressure? Would disturbing the luxury lifestyles of his oligarchs help?<br> <br> Max Jeffery talks with Katy Balls and James Forsyth about whether cutting off Russia's super-rich might be the way to topple the Russian leader. </div>