Sachs' principle concern is nuclear war and always has been. I wrote him a couple letters arguing with him when he was just a chin-stroking intellectual with a monthly column in Scientific American - at one point even excoriating him for a convenient but wrong interpretation of the Cuban Missile Crisis (which I happen to think was an American blunder in which the world was saved by the Americans backing down) where I was taking the side of the USSR. I think if you start from the viewpoint "Vladimir Putin will end the world on a whim" you end up a lot more sympathetic to Sachs' arguments.

I, on the other hand, doubt Russia has any nukes. They haven't tested anything since 1990 and their arsenal is maintained by the same conscript core that maintains their tires. yeah, they could probably light up their arsenal and get 20-30% non-duds but it took them the better part of 36 hours to be ready to go back when they knew what they were doing. That, combined with an insight into Russian command & control described by Thomas Rid as "exquisite" in reference to the Discord Leaks, lead me to believe that the American optimization on the Ukraine War is "keep them covered and watch them die."

Charitably - I suspect some of the fellow travelers would take an abrupt right turn if they weren't concerned with armageddon. If he were more worried about Ukrainian lives than his own we'd probably agree more.