Sentence:  So , while we properly inveigh against the new poisoning , history is not likely to justify the pose of righteousness which some in the West <WSD>were</WSD> so quick to assume when Mr. Khrushchev made his cynical and irresponsible threat . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)