The conflict in Ukraine is driving a modernization of NATO weaponry, honing the alliance’s ability to face off against Russia and adding to the list of unintended consequences from Moscow’s invasion of its smaller neighbor. Former East Bloc NATO members have been arming Ukraine with Soviet-designed equipment similar to Kyiv’s existing gear. That has permitted a military housecleaning of their own arsenals on a scale that would have been unimaginable months ago. In turn, the North Atlantic Treaty Organization will help its eastern members replace those arms with newer ones, greatly improving efficiency.