The Russians seem to have recovered the Crimean bridge very quickly—cars were running through it within hours; and they also claimed to have sent a train through, although that was pure propaganda—it will be time-consuming to recover the burnt-out train in the middle of the sea (not to mention the structural issues). So was it worth it for the Ukraine? I thought that at first—yet I had forgotten that war is mostly psychological: the bridge is a prestige Putin project that symbolises the link between Crimea and Russia—to disrupt it is a huge psychological blow, a personal blow to Putin. Additionally, Russian soldiers at the front will feel that their supply lines are compromised—whatever the reality. Trains allow for bulk transport—particularly of tanks—so there may be some material issues; yet, overall, the main impact is to make them feel precarious and vulnerable—no help is coming (not from that direction anyway).
So far the Russians have not responded, although they could have loosed a few missiles instantly. Why not? They are weighing their options, proportionally they will want to do something spectacular—probably against a prestige target. They have already retaliated in one deniable way—FSB elements in Germany sabotaged rail lines. This will never be acknowledged, but it was a message to the West—since the West facilitated the operations against Dugin’s daughter and the Crimea bridge (for the same reason “unidentified” drones buzz North Sea oil rigs—the Russians implicitly threaten to sever North Sea oil and gas in time for winter, just as they took out Nord Stream).
Yet the deniable action is not the “official” response, just a snap warning shot across the bows for Washington. Actions continue to be escalatory: Nord Stream is partially German, so Russia has committed two acts of war against Germany already. To deploy sabotage networks in Europe is in line with scenarios outlined by Western planners for the opening phases of a Soviet-NATO confrontation—aka WWIII.