Sentence:  The enormous changes in world politics have , however , thrown it into confusion , so much so that it <WSD>is</WSD> safe to say that all international law is now in need of reexamination and clarification in light of the social conditions of the present era . ) 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)