> Several concurrent arms races in the Middle East, Asia, and Europe
Which is to say, possible future proxy wars between the great powers where MAD will supposedly restrict conflict intensity. See below.
> A high intensity conflict in Ukraine
What's going on in Ukraine is a bog standard cold war style proxy war. The NATO plan is basically to turn it into another Afghanistan for the Russians. It's the exact thing that MAD is meant to keep from spilling over into a world war between the principals.
> China threatening a land invasion into Taiwan
This is more interesting. US conventional forces almost certainly have no hope of beating China that close to home. Therefore, any effective US response would require nuking China and China is presumably deterring that with their nukes. There is an argument to be made here that a non-nuclear Chinese military would be in Taiwan's best interests. However, I see no scenario where either a nuclear or non-nuclear China and a non-nuclear USA is in Taiwan's best interests. So while the MAD case isn't the best case for Taiwan here, it's also not the worst.
Which is to say, possible future proxy wars between the great powers where MAD will supposedly restrict conflict intensity. See below.
> A high intensity conflict in Ukraine
What's going on in Ukraine is a bog standard cold war style proxy war. The NATO plan is basically to turn it into another Afghanistan for the Russians. It's the exact thing that MAD is meant to keep from spilling over into a world war between the principals.
> China threatening a land invasion into Taiwan
This is more interesting. US conventional forces almost certainly have no hope of beating China that close to home. Therefore, any effective US response would require nuking China and China is presumably deterring that with their nukes. There is an argument to be made here that a non-nuclear Chinese military would be in Taiwan's best interests. However, I see no scenario where either a nuclear or non-nuclear China and a non-nuclear USA is in Taiwan's best interests. So while the MAD case isn't the best case for Taiwan here, it's also not the worst.