Britain and America present themselves as the heroes of the 20th century. The various wars are not seen as a successful spreading of Anglo cultural, linguistic and economic values across the rest of the globe. Rather, it was several heroic defences of freedom against tyranny.
This vision gets strained when one looks at the biggest 'Blowback' in world history, the defeat of Britain and France by Hitler's Germany. Most of the Tory party had supported Hitler as a valuable ally against Communism, and they had indirectly helped Fascism win in Spain against a radical government that was democratically elected.
But then they got into an argument over the dismantling of Czechoslovakia, which Britain and France found useful but which Hitler wanted to abolish. Somehow, powers that were basically in sympathy with each other managed to blunder into a confrontation, in which each in term would seek support from Soviet Russia.
This era was later called 'Appeasement', and appeasement is the term used for any compromise that anyone disapproves of. If they like it, the process is 'compromise' or 'conciliation'. But where does the difference come from? According to the Oxford English
Dictionary (CD-ROM 2.0), appeasement is:
1. The action or process of appeasing; pacification, satisfaction...
4. Freely used in political contexts in the 20th century, and since 1938 often used disparagingly with allusion to the attempts at conciliation by concession made by Mr. Neville Chamberlain, the British Prime Minister, before the outbreak of war with Germany in 1939; by extension, any such policy of pacification by concession to an enemy.
I'd already concluded that 'John Bull speaks with a forked tongue' from my general knowledge of British foreign policy (and domestic policy also, when you look at it dispassionately). The current negative overtones attached to 'Appeasement' may have been a genuine shift in meaning caused by popular opinion. But in other cases, you find evidence of the deliberate creation of a false split between 'them' and 'us'.