Sentence:  The editors condemned the claims of one of the board members, that he was "acting in full accord with [what] the "Forward" was preaching," as an attempt to discredit the paper's principled opposition to the war, and characterized his plea as "an effort to <WSD>throw dirt</WSD> upon the entire East Side." 
Meaning of the word marked with <WSD> tags:  To make derogatory or malicious allegations, particularly about people in public life.