Sentence:  Insofar as these nations claim to incarnate traditions and ways of life which constitute ultimate , trans-political justifications for their existence , such people are inevitably led to emphasize the ways in which these traditions and ways <WSD>are</WSD> theirs rather than someone else 's . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)