Why is Putin Taking ‘a Colossal Gamble' Invading Ukraine?

We don't know what's going on in Vladimir Putin's head as Russia invades Ukraine, says Anatol Lieven, an author and senior fellow at the Quincy Institute for Responsible Statecraft. It seems like Russia wants Ukrainian President Volodymr Zelenskyy to surrender and agree to demilitarize, but there does not appear to be a concrete plan to replace the Ukrainian government.