Amid the avalanche of anti-Israel incitement from European sources on a daily basis, Martin Schulz’s comments about Israeli water usage and Gaza might not have drawn much attention if he had not uttered them in German when speaking before a session of the Knesset. Schulz, the president of the European Union parliament, was in Israel for a goodwill visit and most of his address to Israel’s lawmakers yesterday was fairly innocuous. He praised Israel’s democracy, decried terrorism, opposed Iran’s attempt to gain nuclear weapons and called for a two-state solution that would end the conflict with the Palestinians. So far, so good. But then, almost as a throwaway line, the German politician, who is a candidate for president of the far more powerful European Commission that runs the EU, claimed that Israel was not only stealing Palestinian water but restricting the supply used by Arabs. He also lamented what he said was Israel’s “blockade” of Gaza, an implicit accusation that it was causing a humanitarian crisis there.

As it turns out, Schultz’s accusation that Israelis use 70 liters of water a day and the Palestinians only 17 was not fact-checked before he uttered it. While there are various estimates of water use, even the lowest figures for the Palestinians are more than four times that number and others as high as six times. Talk about a blockade of Gaza, which is supplied with electricity by Israel as well as daily shipments of food and medicine, is similarly misleading. Why would a high-ranking EU official casually toss of such phrases and then express surprise and anger when some of the Knesset members present responded by angrily walking out? The answer goes deeper than a discussion of the admittedly difficult subject of water allocation or the facts about Gaza. What Schulz’s speech shows is how pervasive anti-Israel invective has become. If even a politician looking to mend fences thinks there’s nothing offensive about saying such things, this should serve as a wake-up call to Israel’s friends that they must redouble their efforts to tell the truth about the Jewish state and the Middle East conflict.

As the Times of Israel reported today, Schulz’s comments about water allocation were completely false. While Palestinians have access to far more water than he claimed, it’s true that Israeli consumers are served better because of the country’s vast desalinization efforts. Palestinians are also handicapped by the corruption and incompetence of governments in the West Bank and Gaza that prize confrontation with Israel over development. The situation would be rectified by peace, but this aspect of life in the region, like so many others, has been held hostage by Palestinian intransigence that makes a solution to the conflict impossible.

Nevertheless, many Israelis were embarrassed by the Knesset walkout as well as by the intemperate response of Economy Minister Naftali Bennett, who didn’t hesitate to invoke Germany’s past when be blasted Schulz:

I will not accept a false moralizing narrative against Israel in our parliament, in our Knesset. Certainly not in German.

Bennett’s words probably didn’t win the Jewish state any new friends in Germany. But rather than focus on his lack of diplomatic finesse, the lesson here has to do with a failure of information rather than of good manners.

Many Israelis and their friends abroad have focused in recent years on efforts to “rebrand” their country as an attractive tourist destination or a source of high-tech innovation. Others have insisted that Israel’s image will never be improved until peace with the Palestinians has been reached. These strategies have helped instill a certain degree of complacency, if not apathy in a pro-Israel community that has come to accept slanders and false information about the Jewish state as something that is bad but about which nothing can be done.

It is true that much of the anti-Israeli invective coming out of Europe has its roots in anti-Semitism, whether imported from the Middle East by immigrants or the product of anti-Zionist incitement from intellectual and academic elites. But the offhand nature of Schulz’s utterances should tell us that there is no substitute for an energetic effort on the part of Israelis and their foreign friends to answer any and all such libels. By assuming that intelligent people won’t believe slanders, they let lies like the water statistics become a form of conventional wisdom that is difficult to correct once accepted by the public.

It is not enough to get mad about speeches such as the one given by Schulz. The lies must be actively refuted. That won’t stop the deluge of hate speech directed at the Jewish state but it will make it harder for politicians like Schulz to create diplomatic incidents by passing along widely-held beliefs that are not true.