Alright this one is pretty simple. Government official A + Government official B [New Jersey pols]. These pols are by definition, "government reps."
Now for the other half of the phrase: Dictionary definition of "restrict": "to keep within limits; confine."
Are you so out of bounds as to not recognize an attempt to keep sales "within limits" or is the dictionary a mystery novel to you?
Let's put it all together in context: the Jersey pols' own joint statement reads: "No one in New Jersey should buy this book and allow Ann Coulter to profit from her hate-mongering."
So, now allow me to go to my Dictionary of Synonyms and Antonyms: When a Jersey pol publicly campaigns to have you as a voter vote for him or her, that is the opposite of restrict: He or she is seeking to "widen, expand, extend, and enlarge"[antonyms to restrict] his or her voter base. Now, when those same Jersey pols publicly campaign for stores not to stock a certain book, that means they are seeking to "limit, restrain, impede, confine, check, bind, curb, fence, crimp" [synonyms to "restrict].
There, crystal clear now?