A lot of deterrence credibility depends on at least pretending you think you can get into a fight without it inevitably going nuclear.

After all, if America’s military thinkers all believe if America fought China it would inevitably result in mutually assured destruction - then American security guarantees for Taiwan lose all credibility.

Most American military planners assume that if China invades Taiwan they'll use smaller "tactical" nuclear missles to do things like destory carrier groups to test the will of the US on MAD. Predicting, probably correctly, that the US will not respond with a full scale nuclear strike in response to the destruction of a military target just because nuclear weapons were used.