11.The ISW said Russia had treated its border with Ukraine as a "dormant frontline," that clearly did not have the level of military resources required to defend against such an attack."Russia's prolonged treatment of the international border area as a dormant frontline is a strategic failure of imagination," it said.The Ukrainian military launched a surprise incursion across the border into Kursk Oblast on Aug. 6, bringing regular Ukrainian forces into Russia for the first time.Although reinforcements sent by Moscow have begun to arrive on the battlefield, Ukraine has reportedly continued to advance farther into Kursk Oblast."Russia has spent considerable resources to build fortifications along the international border area but has not allocated the manpower and materiel to significantly man and defend those fortifications," the ISW said.It added that Ukraine's offensive will likely force the Kremlin to shift resources from inside Ukraine to defend the border regions.