Land based ICBMs are more accurate than SLBMs and would launch in retaliation.
The US has stealth cruise missiles it can launch from bombers.
The US has the B1 and B2 bombers that can deliver nukes.
Many Navy ships can launch nuclear cruise missiles.
The USA is the only superpower that has such robust nuclear weapons delivery via a triad (land, air, sea). With Russian SLBM subs it is said they are so noisy that US attack subs are always silently tailing them after they leave port and can take them out before they can launch. Russia and China really only have robust land-based ICBMs. If all of those could be preemptively attacked (by stealth strikes and commando raids) then the US could potentially win a nuclear war. Not that we'd want to try.
