JG54,
Are you suggesting that launching a preemptive nuclear strike on Britain is less crazy than invading contiguous countries with conventional forces?
I of course accept that Russia's conventional forces are not what they once were, but then neither are ours. Do you really think we would prevail "toe to toe"?
As for standing off in WW2, I was not intending any criticism of judgement or our forces, but a read of Churchill's war diaries would show you the lengths we and the US went to to ensure the Red Army did the heavy lifting against the Wermacht. The casualty figures are a shorthand version of the story.
To put my argument another way, I think the only nuclear threats we should be worrying about come from people (terrorists) who we cant launch retaliatory strikes against. Putin's interests lie in retaking territory on his borders. He has the conventional means to do this, and we (NATO) have neither the means nor the inclination to do much about it. At best, we would impose sanctions. Oops, we've already done that.....
In any event, Trident and its successor don't seem to give us a lot of strategic options and cost a fortune. We would have a lot more options if we used the money on our conventional forces