Sentence:  At any rate , the substance of Eichmann 's testimony was that all his actions flowed from his membership in the party and the SS , and though the Prosecutor did his utmost to prove actual personal hatred of Jews , his success on this score <WSD>was</WSD> doubtful and the anti-Semitic lesson weakened to that extent . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)