Ukrainian forces have hit a Russian air defence battery on Russian territory in what is thought to be the first use of US-made HIMARS rockets since Biden allowed their use in cross-border Ukrainian attacks. The Ukrainian side hasn’t commented yet but the Institute for the Study of War, citing Russian sources, says the rockets struck a battery near Belgorod about 80 km from Kharkiv. This would have been out of range of all multiple rocket launch systems at Ukraine’s disposal other than HIMARS. UK, Canada and most EU countries – including Germany, whose Chancellor Olaf Szcholtz is probably Europe’s most cautious leader about confronting Russia militarily – have also allowed Ukraine to strike Russian territory with Western weapons. Could ending this taboo be a game-changer on the battlefield?