US is very obviously not dominant in nuclear delivery systems given that both Russia and China have hypersonic weapons while US does not. There's also no indication that US has any superiority in submarines or other forces. In fact, US airforce admits that they don't actually have superiority over China https://www.airandspaceforces.com/air-force-rethink-air-superiority-allvin/
The war US is obviously thinking about is one with China because China is surpassing the US now.