The US were allegedly signing significant trade deals with the UK as soon as Brexit was completed but as yet haven't, which makes you wonder how deep the special relationship goes. Nuclear war has been averted for decades because of the threat of mutually assured destruction which was always on the assumption of an attack either by Russia on the US or visa versa. War is normally to gain land or the access to mineral wealth (or the rights to it) Would the US stand back to see which way the wind blows, having a third party mortally wound Russia without direct risk to themselves could have great benefits.