There has been vast debate over this ship: whether she should be built; where she was to be built; whether she was worth the estimated cost; whether she should have cats and traps allowing more effective planes and the suggestion that she might be retrofitted with them; whether she should have been nuclear powered; whether the planes are going to be good enough; whether the navy should have one or two of these carriers etc. etc. Those interested in defence have argued about these issues for years and the naming of HMS Queen Elizabeth will not stop that debate.
There are a number of fundamental problems about defence spending like this. It keeps high skilled jobs, provides for increases in technology which may be useful in other spheres, provides for potential subsequent export sales etc. Yet it costs vast amounts of money which could be used elsewhere.
Then there is whether or not a country needs weapons technology of this sort and whether having such weapons makes a nation safer or not.
Having a large military helped in Eden launching the Suez campaign: one of the greatest foreign policy disasters of post war Britain. Despite having a much smaller military Tony Blair used the UK’s still significant armed forces to assist in what is arguably the greatest foreign policy disaster since Suez: Iraq; as well as assorted Balkan adventures.
One could argue that having a large military and defence spending allows politicians to indulge dangerous fantasies of military adventurism which result both in periodic foreign policy debacles and the deaths of thousands.
The deterrence value of sophisticated weapons systems may be of limited significance in the current world of terrorists. Equally, however, against the possibility of conflict with another technologically advanced military nation one needs modern weapons. The disaster by which Britain was chased off the continent by Hitler’s divisions in 1940 would likely have been much worse had money not been spent (albeit belatedly) on state of the art aircraft and ships.
Of course had more money been spent earlier maybe Hitler might have been stopped earlier or indeed might have been deterred in the first place.
One does not need to invoke Godwin’s Law, however, to see the utility of deterrence. A better example, might be that in the 1960s there were proposals to build two large aircraft carriers for the Royal Navy (which were to be called HMS Queen Elizabeth and HMS Duke of Edinburgh). Had those massively expensive ships been built retaking the Falklands would have been vastly easier (although the Americans helped the British it is suggested that they assessed retaking the Falklands as militarily impossible).
Equally of course had the Royal Navy had two fairly new full sized carriers in 1982 it is more than possible that Argentina would not have attempted to take the Falklands in the first place. That would have saved many times the value of the carriers in monetary let alone human life terms but we would never have known that they had had such an effect: such is the nature of deterrence. Finally, had Britain had those two carriers and then there been no Falklands War, Thatcher’s reputation and the 1983 election might have been different.