Sentence:  But while there remains a considerable degree of consensus that the consequence of apparently <WSD>losing the plot</WSD> sometime between 1914 and 1918 was the cultural and economic malaise of the 1920s and 1930s, there are still some who look back on the interwar years less with criticism than with nostalgia. 
Meaning of the word marked with <WSD> tags:  To lose sight of an important objective or principle; to act contrarily to one's own interests through concentrating on relatively unimportant matters.