The end point of that (hypothetical) arms race would be China in 15-25 years having its own Starship clone, and thousands of nuclear weapons in low Earth orbit.

The end point of that (hypothetical) arms race would be China in 15-25 years having its own Starship clone, and thousands of nuclear weapons in low Earth orbit. Their purpose being that you could de-orbit a nuclear weapon nearly instantly, evading the other side's space-based intercept capability. (An ICBM, by comparison, would be a sitting duck to space-based interceptors, with its 30-minute long, predictable, trajectory). Would we be better off? We'd be in the same position (MAD), only a trillion dollars shorter and also nuclear war now has a 30-second latency instead of a 30-minute one. And also we've created a novel type of nuclear instability: one where we have the possibility of a preemptive strike by orbiting interceptors against orbiting nuclear weapons, one that happens in seconds and is determined entirely by AI. False positives and false negatives are both extinction events.