A newly reported operation suggests Kyiv may have found another low-cost way to disrupt Russian forces away from the front line: heated insoles allegedly rigged with small explosive charges and sent through volunteer aid channels. According to Ukrainian outlet Militarnyi, operatives from Ukraine’s special services allegedly inserted explosive-filled heated insoles into shipments destined for Russian military units. The items were reportedly moved with the help of Russian volunteers and charitable foundations, allowing them to pass as ordinary humanitarian aid. That is what makes this sort of sabotage effective, Treston Wheat, chief geopolitical officer at Insight Forward, told me: it exploits...