Trident Replacement?

We have yet to hear, but I guess we might hear very little now from the Lib Dems in coalition government about opposition to Trident replacement. Their policy was a little like their Iraq war policy in any case (They opposed the war until it started , then "supported our boys", whilst loudly trumpeting at subsequent elections that they had been the "anti-war party". For Lib Dems anti-war presumably means until it starts then.) They said they were anti- Trident replacement, to win the anti-nuclear and peace vote and to be seen to be making savings, whilst quietly saying that they were really interested in a "cheaper alternative". So that is alright then - Lib Dems are only in favour of cheap weapons of mass destruction.
Nevertheless, the Lib Dems policy in the election campaign (presumably now quietly dropped) launched a lot of anguished shrieking about "deterrence" in a world of dangers from the big two establishment parties and the establishment media.
I had this thought the other day about the so called "Deterrence" argument.
The argument for deterrence implies that your potential enemies must be convinced that if attacked, your country will respond with devastating nuclear force. However, anyone who would launch a nuclear attack potentially killing and maiming millions of people would be by definition a war criminal and by implication a genocidal maniac and sociopath. So an ememy must be convinced that your defence is in the hands of genocidal maniacs. And the only way you could really convince their intelligence services of this would be to have people in post who were indistinguishable from such maniacs - such that *no-one* could tell whether they were or not. Otherwise deterrence would not be credible. So in effect, deterrence means handing over your defence to genocidal maniacs - the sort of people who might launch a nuclear attack in any number of circumstances! I do not think most people realise this implication and think this would be a very scary realisation for most people, if they really thought about it.
(Although of course, the British Independent Nuclear "Deterrent" is neither fully British, Independent or a Deterrent - how do you deter suicidal terrorists?)
With the importance the British establishment places on "British" nuclear weapons, one wonders how most of the countries of the world can live from day to day, being in constant fear of nuclear attack or blackmail as they must be, "unprotected" by "their own" nukes? Or then again, perhaps they are not in constant fear, save a lot of money and do not live with expensive and redundant Imperial hangups.......