WASHINGTON (AP) — Western weaponry pouring into Ukraine helped blunt Russia’s initial offensive and seems certain to play a central role in the approaching, potentially decisive, battle for Ukraine’s contested Donbas region. Yet the Russian military is making little headway halting what has become a historic arms express. The U.S. numbers alone are mounting: more than 12,000 weapons designed to defeat armored vehicles, some 1,400 shoulder-fired Stinger missiles to shoot down aircraft and more than 50 million rounds of ammunition, among many other things. Dozens of other nations are adding to the totals. The Biden administration is preparing yet...