After weeks of military buildup and lies, Russia has attacked Ukraine. We are watching a worst-case scenario — a full invasion by land, sea, and cyberspace — play out in real time. With diplomacy dead, Western allies are now turning to sanctions.

The mood was somber at the recent Munich Security Conference, where world leaders were scrambling to avoid exactly this outcome.

On GZERO World, Ian Bremmer talks to former CIA boss David Petraeus to discuss the "porcupine" Vladimir Putin has eaten, and to John Kerry, former US Secretary of State and the Biden administration's current climate czar, about Putin's other big problem with climate.