In past centuries, identifying the world’s leading antisemites was not a problem. With respect to classic religious antisemitism, the Catholic Church dominated this type of hate mongering. Throughout generations Jews were accused of being responsible for killing God’s alleged son Jesus. This was a lie. Only the Romans – during their occupation of Judea – could condemn somebody to death and then carry out the execution.In addition holding people responsible for what their ancestors have done – and in this case did not do – is a hate promoting approach which, when applied systematically, poisons any society. Later, some Protestant leaders joined the antisemitic inciters, Martin Luther was prominent among the worst.Upon this infrastructure of extreme Christian incitement against Jews a second type of classic Jew-hatred developed in the nineteenth century: ethnic/nationalistic antisemitism. In this area Germany had no competition when it – with the help of European allies – carried out the Holocaust In today’s ideologically fragmented societies, the sources of antisemitism are many and widespread. In this multitude some antisemitic perpetrators and incidents stand out because of what they do or say and who they are. Identifying these inciters provides a perspective on the severity of their acts.Major areas of this problem include Muslim antisemitism, right and left-wing antisemitism as well as anti-Israelism.A speech given in 2003 by the Prime Minister of Malaysia, Mohamad Mahathir, stands out for its hatred of Jews and the widespread approval of it. He spoke at the opening session of the tenth summit of the Organization of Islamic Cooperation held in Putrajaya, Malaysia.Mahathir represented relations between Muslims and Jews as a worldwide frontal confrontation. He said: “1.3 billion Muslims cannot be defeated by a few million Jews.”The meeting was attended by leaders of 57 countries representing almost the entire Muslim dominated world. They applauded his speech.Muslim mega-antisemitism is genocidal. Iran’s leaders openly promote genocide against the Jewish state. They are also responsible for the largest terrorist attack against Jews in the post-World War Two period which took place at the Amia building in Buenos Aires in 1994.Also Hamas and Hezbollah promote genocidal antisemitism.Furthermore, most ideological murders of Jews in this century in Europe – of which the perpetrators are known – have been committed by Muslims. Nothing is comparable to the extreme hate of Jews and Israel coming out of parts of the Muslim world. There are no other heads of state, right-wing or left-wing, who promote genocidal antisemitism or a total confrontation with Israel and Jews worldwide.However unpleasant right-wing antisemitism is in the current environment of hate, no mega-organization towers above the others. The Greek Golden Dawn movement has never been in power. Some of its leaders are in jail and Greece is not a country with major influence. Hungary’s Jobbik is trying to become more moderate in order to attract additional voters.Anti-Israelism is the third type of antisemitism. On the extreme left one can find many who would like Israel to disappear. This can only happen through genocide.A major leftist current of thought is that the world is divided into oppressors and the oppressed. The oppressors are supposedly all white including Israel and the Jews. These people intentionally ignore the easily to be seen truth that most people killed in armed conflicts in this century are Muslims murdered by other Muslims.This group of antisemitic extreme leftists are not heads of state and do not have much influence.In the mainstream Left, we find extreme anti-Israel inciters in a variety of socialist parties. Currently, the worst Western example is the British Labour Party headed by Jeremy Corbyn who possibly may win the next parliamentary elections. Labour is, however, far from being dominated by antisemites. At the same time, the majority of party members are whitewashers of antisemitism.The three main socialist leaders who compared Israel to the Nazis have died: Swedish prime minister Olof Palme, Greek prime minister Andreas Papandreou and French president, Francois Mitterand.Media is another major source of left-wing antisemitism which predominantly focuses its hatred on Israel. One of the vilest European antisemites was the German Literature Nobel Prize winner, Gunther Grass. This leftist writer was in his youth a member of the Waffen SS. In 2012, he claimed that Israel intended to commit genocide against the Iranian people with nuclear bombs.He must have known that the reverse was true. Iranian leaders had regularly threatened Israel with eradication.If a Nobel Prize winner had any chance in the mega-antisemites competition, Portuguese author Jose Saramago would also be a contender.He compared the most flourishing Palestinian town of Ramallah to Auschwitz.Grass only became a mega-antisemite when his hate-poem received huge publicity from six European mainstream papers with millions of readers. These were the German Suddeutsche Zeitung, the Italian La Repubblica, the British Guardian, the Spanish El Pais, the Danish Politiken, and the Norwegian Aftenposten.One may also wonder about contemporary Christian antisemitism.In 1965, the Vatican issued the Nostra Aetate document, the declaration of the relations of the Church with non-Christian religions. This statement greatly reduced Catholic antisemitism.Substantial antisemitic hate, mainly focused on Israel, but also sometimes on the Jews comes out of parts of the Protestant world. However it is difficult to find very important Christian groups with extreme positions.The World Council of Churches incites against Israel. Two liberal American protestant denominations promote BDS. The number of members of both, the Presbyterian Church and the United Church of Christ, have been declining and are expected to continue to do so. Several Eastern Churches can also be mentioned as promoters of Jew-hate. One should not forget Jewish anti-Israel organizations and individuals. Fortunately, their influence is too small to make it to the premier league of antisemitism.Finally there are those who indirectly support the Palestinian genocide promoters. Among these the United Nations and several of its associate organizations stand out.The author is the emeritus chairman of the Jerusalem Center for Public Affairs. He was given the Lifetime Achievement Award by the Journal for the Study of Antisemitism, and the International Leadership Award by the Simon Wiesenthal Center.