After three weeks of fighting, Russia is still struggling to dislodge Ukrainian forces from the Kursk region, a surprisingly slow and low-key response to the first occupation of its territory since World War II. With the bulk of its military pressing offensives inside Ukraine, the Kremlin appears to lack enough reserves for now to drive out Kyiv's forces. President Vladimir Putin doesn’t seem to view the attack — or at least, give the impression that he views it — as a grave enough threat to warrant pulling troops from eastern Ukraine's Donbas region, his priority target.