Sentence:  Mr. Truman has only to recall the `` hopeless '' campaign of 1948 to remember what a loyal partisan he was and the first experience of Mr. Kennedy with Congress would have been sadder than it <WSD>was</WSD> had not Mr. Sam been there . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)