Might the European Union face a complete halt of gas supplies from Russia? The European Commission fears so. The EU executive arm proposed that member countries voluntarily reduce their gas consumption by 15% to be ready for such an eventuality, while requesting powers to impose mandatory targets if necessary. The EU wants to be able to ensure emergency transfers of gas to members who face shortages deep in winter if supplies drop to critical levels. The move would ease Russian President Vladimir Putin’s leverage over the 27-member EU. But the approach is testing European solidarity, with some…