Our “old and decrepit” Trident boats are still the quietest SSBN in the world. And they carry 24 of the D-5 missile, capable of an effective Nuclear Counterforce first strike.
From at least 7,000 miles away.
Or, if up close they can put a warhead on target in less than 10mins. Or even 100 of them.
And we have more than a dozen. 2-3 on patrol at all times.
The Trident D5 has an upgraded guidance & fusing package that some say is as accurate as a land based missile system. Scary-stuff if you’re an adversary.