This is from Haaretz.
So it seems that one reason for talking to Iran is to legitimate action taken by the U.S. or Israel! It seems that if the Iranians do not give in to U.S. demands then action is legitimate!
Obama to PM: Iran action legitimate only if talks fail
By Barak Ravid and Jack Khoury, Haaretz Correspondents
Tags: Ehud Olmert, Barack Obama
Near the close of his visit to Israel on Wednesday, Democratic presidential hopeful Barack Obama met with Prime Minister Ehud Olmert. A major topic of their long conversation was Obama's declared willingness to engage in direct dialogue with Tehran. Obama reportedly told Olmert that he is interested in meeting the Iranians in order to issue clear ultimatums. "If after that, they still show no willingness to change their nuclear policy, then any action against them would be legitimate," an Israeli source quoted him as saying.