There are questions about who would be launching all-out nuclear war on the US when there are such obvious and effective indirect means of destruction.

If you want to destabilise an economy, destroy science and R&D, nuke healthcare, ruin decades of trust with allies, disassemble democratic checks and balances, co-opt the media, and give most of the population a nervous breakdown that has them believing batshit divisive nonsense, you certainly don't need nuclear weapons to do it.