To many readers the New York Times coverage of the war in Gaza comes across as neutered or as having a pro-Israeli bias. But not to Ron Dermer, the Israeli ambassador in Washington, who lambasts the paper for failing “to mention that a million Israelis were in bomb shelters yesterday as 100 rockets were fired at our civilian population.”

Mr Dermer is considered so close to Israeli Prime Minister Benjamin Netanyahu that he has been called “Bibi’s brain”. He is also a former student and employee of Frank Luntz, the Republican strategist who produced a confidential booklet in 2009, promptly leaked, advising Israeli spokesmen how best to manipulate American and European public opinion. “Don’t confuse messages with facts,” Dr Luntz advises the spokesmen as he explains how facts should be selected and best presented to make Israel’s case.

It is a sophisticated document based on wide-ranging opinion polls, suggesting, for instance, that the removal of Israeli settlements from the West Bank should be denounced as “a kind of ethnic cleansing”. Dr Luntz stresses that spokesmen must demonise Hamas, but above all emphasise that they feel for the sufferings of Palestinians as well as Israelis. As a sample of what they should say, he gives: “The day will come when Israeli children and Palestinian children will grow up together, play together, and work together side-by-side not just because they have to but because they want to.”

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The problem about this approach is that it sounds particularly hypocritical when, according to Unicef, 230 children have been killed in Gaza, an average of ten a day, and 2,000 have been wounded by Israeli bombs, shells and bullets. Israeli spokesmen are now denying their responsibility for the most notorious and televised atrocities such as the strike on the UN hospital last week. This is an old PR tactic, though not one recommended by Dr Luntz, which is sometime referred to as “first you say no story, then you say old story”. In other words, deny everything in the teeth of the evidence on day one and, by the time definitive proof of the massacre comes through, nobody notices when you have to admit responsibility.

Video: The latest from Gaza

A problem here is that propaganda that works in a short war comes back to haunt you in a longer one. This is now happening in Gaza. Israeli air and artillery strikes and Hamas mortars and rockets are often presented as if they balanced each other out in terms of lethality. But the most important statistic here is that some 1,100 Palestinians have been killed as opposed to three civilians in Israel.

Despite his tutoring by Dr Luntz, Mr Dermer only speaks these days to the converted. Attending a Christians United for Israel Summit in Washington he replied to protesters who called him a “war criminal” by saying that “the truth is that the Israeli Defence Forces should be given a Nobel Peace Prize”. Stuff like this may explain why a Gallup poll shows that among Americans aged between 18 and 29 some 51 per cent said Israel’s actions were unjustified while only 23 per cent said they were.

For all the good advice of Dr Luntz there are signs of Israeli leaders getting rattled. Mr Netanyahu complained on CNN that Hamas wants “to pile up as many civilian dead as they can” and “to use telegenically dead Palestinians for their cause.” Even the best propaganda machine cannot explain away massacres of civilians as happened in Lebanon at Sabra and Shatila in 1982 and at Qana in 1996 and 2006.