A year ago, sending NATO battle tanks to a non-NATO nation fighting a war against Russia would've been unthinkable. Kyiv’s long campaign for support from western nations seemed to fall on deaf ears, even though many experts agreed that the need was there. Now, however, Germany, Denmark, and other European nations are sending Leopard 1 A5 and Leopard 2 A6 tanks to Ukraine; Britain has sent a squadron of Challenger 2s; and the U.S. is sending a battalion of 31 M1A2 Abrams tanks.