Anti-Semitism is back – though it can be argued that it never went away. The real focus of our attention should be in the United Kingdom with the rise of Jeremy Corbyn as the leader of the British Labour party and in effect the head of the Opposition.

If you’re not following how this story is unfolding, the details are extremely important. Look at what British leaders themselves are saying. This month, the deputy head of the British Labour party, Tom Watson, in fact declared that the British Labour party is in danger of disappearing “into a vortex of eternal shame” over the issue of anti-Semitism. So this is not just an observation made by parts of the Jewish community. It’s an observation, in fact, made by the most central parts of Britain’s political establishment, and the British press is not at all reluctant to report.

In the Jewish community, the three main Jewish newspapers in the UK published a joint editorial that, should Jeremy Corbyn form the next government, that would pose an existential threat to British Jewry.

Much of the concern about Corbyn emanates from fresh revelations of Mr. Corbin himself and his past activities. In 2009, for example, he called Hamas and Hizbullah friends. Hamas was using suicide bombers to blow up buses in the heart of Israel cities in Haifa, Tel Aviv, and of course in Jerusalem. Yet Corbyn advocated removing these organizations – Hamas and Hizbullah – from the UK’s terrorism list.

In 2014 Corbyn visited the cemetery in Tunisia where the leaders of Black September were buried. Remember, they were responsible for the attack on the Israeli Olympic team at the 1972 Munich Olympics, where eleven Israeli athletes were brutally butchered.

Corbyn continuously campaigned to free Samar Alami and Jawad Botmeh, jailed for their role in the 1994 London bombing attacks against the Israeli Embassy in Great Britain and Jewish charity buildings. Recall both of these attacks were perpetrated on British soil and both individuals were prosecuted and found guilty in British courts. So why is Jeremy Corbyn calling this a mistrial and trying to get these two terrorists out of British prison?

Corbyn is also at the heart of the debate in Britain over the definition of anti-Semitism. He’s refused to accept the definition advanced by the International Holocaust Remembrance Alliance – the IHRA – which is, by the way, accepted by 31 countries, 24 of which are members of the European Union. Corbyn and the British Labour party reject four out of eleven examples the definition uses.

He denies that accusing Jews automatically of dual loyalty is anti-Semitic. He denies that questioning the right of the Jewish people to self-determination is a form of anti-Semitism. Finally, he rejects that it is anti-Semitic to compare Israeli policy to that of the Nazis. These caveats that he and his party are advancing allow him to dilute the meaning of anti-Semitism.

This kind of demonization of the Jewish people is classic anti-Semitism. If these doctrines about Israel and Jewish rights become legitimized in Great Britain, which was the fountainhead of so many democracies and states in the world, then there is a real danger that they become legitimized worldwide. And this is something that the State of Israel must firmly oppose and that Britain must not allow to happen.