ROUGH CUT - NO REPORTER NARRATIONbr br STORY: Differences between U.S. President Barack Obama and Israeli Prime Minister Benjamin Netanyahu over setting a "red line" for Iran's nuclear project were never a joking matter.br br Until now, when both leaders uncorked some rapid fire one-liners during Obama's tour of a partially U.S.-funded anti-missile system that he inspected after a red carpet welcome ceremony on Wednesday at Tel Aviv airport.br br "Where do you want to start?" Obama asked an Israeli military official, in a comment picked up by TV cameras providing close coverage of the president and Netanyahu walking together toward the battery.br br "We are following the red line, sir," the officer replied matter-of-factly, referring to a red line painted on the tarmac that led to the missiles.br br "The red line, okay," said Obama, who smiled, gestured with his thumb toward Netanyahu and said: "He's always talking to me about red lines.