Original sentence: As a researcher of contemporary antisemitism, Hirsh is known for coining the term "Livingstone Formulation", after the (former) mayor of London, Ken Livingstone.In Hirsh's formulation, when an individual like Livingstone, with alleged antisemitic attitudes is confronted with this allegation, he immediately reverses the charge, accusing his accuser of "playing the antisemitic card" to stifle debate
Edited sentence: As a researcher of contemporary antisemitism, Hirsh is known for coining the term "Livingstone Formulation", after its effective use by the mayor of London, Ken Livingstone.In Hirsh's formulation, when an individual like Livingstone, with alleged antisemitic attitudes is confronted with this allegation, he immediately reverses the charge, accusing his accuser of  "playing the antisemitic card" to stifle debate