Sentence:  If it <WSD>is</WSD> not enough that all of our internationalist One Worlders are advocating that we join this market , I refer you to an article in the New York Times ' magazine section [ Nov. 12 , 1961 ] , by Mr. Eric Johnston , entitled `` We Must Join the Common Market '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)