Philip Horne at the Times Literary Supplement:
Despite failing health, particularly chronic angina pectoris, James might have completed more books but for the advent of war. He wrote to Edward Emerson on August 4, 1914 that “It has all come as by the leap of some awful monster out of his lair – he is upon us, he is upon all of us here, before we have had time to turn round”. The effect was devastating: “It gives away everything one has believed in & lived for”. British friends and their children were wounded or killed. James flung himself into the war effort – caring for Belgian refugees, visiting wounded soldiers, serving as honorary president of the American Volunteer Motor Ambulance Corps. Though it was draining, James could cherish what he called, writing to Edith Wharton in May 1915, “the unspeakable adventure of being alive in these days”. He was especially tormented by the prolongation of American neutrality in the face of German aggression – to the point of taking the oath of allegiance on July 26, 1915. “Civis Britannicus sum!” he wrote to Edmund Gosse. London friends were pleased. On August 8, he told Rhoda Broughton of the many welcoming reactions to his act of conscience, declaring that “like old Martin Luther, ‘Here I stand, I can no other’”. But his given reasons looked suspect if not downright treasonous to American detractors, and he hoped for relief, as he told Lucy Clifford the next day, from “White’s Spectator thing” of August 14 – Dr J. William White’s article revealing “another and probably a controlling factor” in James’s decision: an “intense dislike for and disapprobation of the official attitude of America since the beginning of the war”, based on “the principles of civilization and of humanity”.
The strain seems to have been too much. On July 30, only four days after his great step, James was again taken ill. His diary would look back: “Date from that day the beginning, with intermissions, very brief, of all this late and present (Sept. 12th) crisis”.