Sentence:  After Cuba and Laos , it was argued , Mr. Khrushchev will interpret the President 's consent to the meeting as further evidence of Western weakness - perhaps even panic - and <WSD>is</WSD> certain to try to exploit the advantage he now believes he holds . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)