John, the points you make are well worth discussing.
Broadly speaking, the sort of capitulation you speak about is rare (unknown?) among the majority of Brits when they perceive the essential national interest to be threatened. With Czechoslovakia in 1938 and Northern Ireland after 1970 they did not.
Lets look at those two examples in more detail. At the time of Munich, most Brits did not believe that events in Czechoslovakia, “a faraway country of which they knew little” (to quote, more or less, Chamberlain) really concerned the security of the UK. That was a view that was perfectly in keeping with Britain’s long, successful and prudent tradition of disengagement from European conflicts. Yes, that policy had been ignored by a small coterie of Liberal Party politicians in 1914, but the disastrous consequences of the intervention they engineered scarred the British psyche both literally (all those butchered or maimed fathers, brothers, uncles and sons) and figuratively: only twenty years after the Armistice there was no enthusiasm for fresh involvement in Europe.
In addition, those objections to the country taking a tougher stance at Munich dovetailed neatly with the pacifist line that had been peddled in Britain by leading opinion-formers since 1918. As a result national tradition, a pragmatic perception of self-interest, mourning for the dead of World War I and the belief that pacifism was somehow morally ‘right’ all combined to come up with the disastrous illusion of ‘peace in our time’. 1939-45 changed all that, and, in particular, ‘1940′ entered the nation’s sense of its self. To a great degree, it still does. I’m not sure that 1938 therefore is much of a precedent.
Looking at Northern Ireland, I don’t think that it is much of a precedent either. As you know, most Brits on the mainland have never considered that province to be fully, well, British. They didn’t in 1970. They don’t now. I suspect that, if you’d polled them in 1970 most mainlanders would have said that they wanted the people of Ulster to sort things out for themselves, almost regardless of what resulted. That hasn’t changed over all this time, and I think it’s that attitude, rather than weakness in the face of terror, that has allowed the UK to acquiesce in the rise to ‘respectability’ of the loathsome Gerry Adams.