Washington (AFP) – Joe Biden has promised to help Ukraine get air defense systems with a longer range than the shoulder-borne Stinger missiles already on the ground, but finding the powerful anti-missile batteries Ukraine’s military so urgently needs is proving easier said than done. The US president, who wants to support Ukraine militarily without entering into direct conflict with Russia, is seeking to provide better defenses against the Russian artillery that is pounding its cities. The ideal armament to do that would be mobile anti-aircraft batteries of the Patriot type, whose effectivene…