You would have hoped that by the 21st century, it would be history, but anti-Semitism has reached what British Chief Rabbi Jonathan Sacks has described as "global tsunami" proportions. Clearly, we are destined to remain "the people that dwelleth alone."
Boosted by the sponsorship of Islamic governments, the world's oldest hatred continues to proliferate, and is once more embedded in the European mindset.
The same Muslims who created a global upheaval calling for the assassination of the publishers of satirical caricatures of the Prophet Muhammad seem to have no qualms about producing and disseminating a rabid Judeophobia that would match the worst of Nazi blood libels. If this were not enough, President Mahmoud Ahmadinejad of Iran -- a nation that is now potentially a nuclear power -- has been shamelessly promoting genocide by repeatedly proclaiming his objective of wiping Israel off the map.
The new anti-Semitism that demonizes Jews and Israel alike has fused itself with the "old" European anti-Jewish bigotry that's enhanced by the growing power of Muslim minorities. At least in the 1930s, powerful liberal voices were condemning Nazi bigotry. Today, many Europeans are in such a state of denial concerning the Islamic threat in their midst that they describe Israel as a greater threat to world peace than rogue states like Iran and North Korea.
Bizarre though it may be, many Europeans even believed that and hold Israel and Jews responsible for terrorist outrages in their own countries. The question is whether Europeans will prove to have learned anything from the failures of their predecessors in the 1930s, who also fooled themselves into believing that appeasing totalitarian regimes seeking global domination would avoid war.
Regrettably, some Europeans are also now starting to mutter that the creation of Israel was a mistake. A number of "enlightened" writers, academics and politicians actually suggest that the "mistake" may even now be rectified.
An almost obscene aspect of this phenomenon is the increasing inclination of assimilated Jews to distance themselves from Israel in the mistaken belief that this may divert the animus directed against them. In Britain, where a groundbreaking parliamentary inquiry confirmed that a "witch's brew" of anti-Semitism had reached record levels, Melanie Phillips, the author of Londonistan, condemned the Jewish leadership for its passivity.
The greatest damage that the current flow of anti-Israeli and anti-Semitic venom can achieve is to undermine the self-confidence of the younger Jewish generation. If they witness cowardly behavior by their parents, what can we expect from them in the future?
The government of Israel must realize that the battle against anti-Semitism affects us directly, as well as the Diaspora. That does not mean that Israel should accept the bizarre advice I once heard a Jewish member of the British nobility convey to prime minister Ariel Sharon, advising him: "Whenever you feel inclined to take reprisals against your Arab neighbors, you should take account of the repercussions on us and first consult us." But we should link far more closely with Jewish communities, and our priority must be to ensure that Diaspora youngsters remain steadfast in their commitment to the Jewish people and Israel.
The reality is that when Israel is perceived as strong and able to stand up to its foes, anti-Semitism tends to decline. Public manifestations of Judeophobia reached their lowest point following the Six-Day War. In contrast, the exponential revival of anti-Semitism can be traced back to the Oslo accords, reaching its climax in the course of Gaza disengagement and during the recent Lebanese war, which were perceived by our enemies as manifestations of weakness.
Unlike the 1930s, there is an Israel, and it is not powerless in the face of anti-Semitism. Together with Jewish communities throughout the world -- not least the influential American Jewish community -- we can defend ourselves. But we must galvanize to confront the barbarians in the war of ideas with no less determination than our adoption of countermeasures against terrorists seeking to bleed us. The decision is ours.
Isi Liebler chairs the Diaspora-Israel Relations Committee of the Jerusalem Center for Public Affairs.