So long as the target is Israel, or Zionism, or even Judaism as a set of ideas, anything goes; equally, any invocation of anti-Semitism on the part of critics is simply a smear to be dismissed.
Who, then, qualifies as an anti-Semite in John Mearsheimer’s world? One has to assume the bar is set very high: you would have to explicitly declare your hatred of Jews as individuals, for instance, or advocate that Jews should sit in separate subway cars. But if you use the Holocaust as a stick with which to beat the Jews, or slyly undermine its “narrative,” or assert that conspiracy theories bear some correspondence to reality, or argue that Jewish government officials are more suspect than others because of their dual loyalty to Israel, that’s not anti-Semitism, he would say — just an honest expression of legitimate opinions.
It’s worth remembering that when the term “anti-Semitism” was coined in 19th-century Germany, its authors were not Jews, but Jew-haters. They wore the badge of anti-Semitism with pride, creating political parties with such names as the “League of Anti-Semites.” The word was owned not by the victims, but by the perpetrators.
In that sense, nothing much has changed. The torrid controversies around anti-Semitism today indicate that the Jewish community has claimed neither the ownership nor the definition of the word. That’s why John Mearsheimer thinks his understanding of anti-Semitism is far superior to yours or mine. And that, you might say, is the greatest scandal of all.
This is the restoration -- the return of "anti-Semite" as a concept to the control of persons and groups generally hostile to the Jewish community. By and large, they would differ from their peers in not consciously adopting the labels (though occasionally you amazingly do see them flirting with it). But what they've done is retake control of the narrative. This runs counter to the general (proper) trend of the last several decades, in which the left has sought to give minority groups more control over how to characterize their victimization, and afforded them substantial (albeit not infinite) deference in when they declare themselves to be wounded.
We saw this with Alice Walker -- the presumed right to define Jewish lives for Jews, to tell Jews when they could and could not be legitimately aggrieved, to tell them what their past history was and what their present entitlements are. It is a restoration of power over Jewish lives. And it won't raise an eyebrow -- because non-Jewish domination over Jews is and always has been the proper state of the world, from which things like Israel are but infuriating anomalies.