First of all, pipelines were not empty. They need to be filled with gas to stay operational on the sea bed. Gazprom turned off pipelines because Germany and Ca

First of all, pipelines were not empty. They need to be filled with gas to stay operational on the sea bed. Gazprom turned off pipelines because Germany and Canada were refusing to return one turbine with proper guarantees and maintain the others (Nord stream one was built with Western turbines, NS2 has Russian ones). Ukraine tried to sabotage NS1 and 2 for many years as both were basically a replacement for the old Soviet gas transport system that fuels Ukraine up to this day. So, they had a very strong motivation to do it. But my bet is on USA, as they have even stronger motive and much greater capability to physically sabotage it.