The United States isolated themselves from European affairs voluntarily; the USSR had been isolated by the attitude of the Four Powers .
Britain was cautious in dealing with any foreign power, even with France , mainly because the French position vis a vis Germany was much more antagonist than the British one.

British Appeasement of 1930s and the Sudeten Issue
Schmidt (1983) sees the appeasement as a form of preventive diplomacy. Since Britain pursued generous social policy during the Ten Years’ Rule (1920s), in fact until the four-year armament plan of 1936, it sought solely peaceful relations with Germany. This strategy meant trying to direct German policy towards greater concern for domestic welfare, thus decreasing the possible conflict in foreign policy area. Abandoning this strategy considerably by presenting the rearmament program in March 1936, Chamberlain remarked: “If only it wasn’t for Germany we would be having such a wonderful time just now...”
Schmidt further illuminates the domestic factors leading to the policy of appeasement. As already noted above, social policy, arms limitation – the so-called “non-war” economy were working well under conditions of peace, but had to be harshly transformed to serve the ‘higher aim’ in the near future, creating thus social tension and loath against the so needed rearmament.
Newman (1978) calls the British foreign policy of this time a “passive pragmatism”, representing continuity in Britain’s Central European policy. The “passive pragmatism” was according to him an inactive policy towards the Danubian Europe adopted to defend British world position throughout the inter-war period. Expressed nicely in words of the foreign secretary, Sir John Simon: Our own policy is quite clear. We must keep out of trouble in Central Europe at all costs. July twenty years ago [1914] stands as an awful warning...”
British situation, as in case of democracies often is, was, among other factors, influenced by the public opinion that was predominantly opposing war. What’s more, many Tory and Labour leaders shared Hitler’s antipathy to the Versailles system. Wilsonian self-determination made the Nazis appear to be on the side of the principle.
Power perception played a great role in 1930s. The game of bluff became the winning strategy for Hitler. The assessment of Hitler’s patience by British Government convinced them that “he would not wait much longer” in the Czechoslovakian crisis. Although the British and French armies were inferior to that of Germany, the information available gave the impression of much greater difference, thus exaggerating and contributing to their appeasement strategy. To sum up, one can observe that Britain’s action was dependent mainly on that of France, and French needed British assurance for getting involved in potential German-Czechoslovak military conflict.