When Ukraine’s military entered the Donbas region in 2014 to put down a separatist uprising, a Ukrainian general described his forces as decrepit, “an army in ruins”. Starting in 2016, Ukraine enlisted the US military to help overhaul its defense systems — everything from recruitment to command-and-control, to how to manage field hospitals. Marco Werman talks about the goals of that reform effort with retired US Army Col. Liam Collins, who spent 2016-2018 advising Ukraine’s defense establishment, and how it has translated into Ukraine’s impressive performance today against the much larger and better-equipped Russian military.