Sentence:  Their writings assume more than dramatic or patriotic interest because of their conviction that the struggle in which they were involved <WSD>was</WSD> neither selfish nor parochial but , rather , as Washington in his last wartime circular reminded his fellow countrymen , that `` with our fate will the destiny of unborn millions be involved '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)