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Not sure if this has been raised, but Israel has engaged in collective punishment practices, for example house demolitions and deportations of relatives of terrorists. It's obviously not on the same level as killing people but the "deterrent" principle is the same.
See: http://www.btselem.org/english/Deportation/Deportation_to_Gaza.asp or
http://www.btselem.org/english/Punitive_Demolitions/20080703_Letter_to_Mazuz.asp
Worked so well they had to build a giant wall.
Personally, I would recommend Friedman travel to Gaza with Marty and Michael as his bodyguards and ask Palestinians if they feel like making nice with Israel now. Something tells me the problem in the Middle East is not a shortage of violence, but I'm no expert like Friedman.