precedent as American policy and in Israeli-Palestinian talks:
As Mr. Obama himself pointed out, his theme in the speech last Thursday was not extraordinary. American presidents, including George W. Bush and Bill Clinton, have consistently instructed their foreign policy aides to pursue an agreement between the Israelis and Palestinians using the 1967 borders, with mutually agreed land swaps, as a basis for talks.
Former Prime Minister Ehud Olmert of Israel, in fact, made such a proposal to the president of the Palestinian Authority, Mahmoud Abbas, in 2008, as the two sides rushed to complete a peace deal before Mr. Bush and Mr. Olmert left office.
But the 1967 border issue has always been privately understood, not spoken publicly, and certainly not publicly endorsed by a sitting American president.
… [Obama] said, “let me reaffirm what ‘1967 lines with mutually agreed swaps’ means.” His view, he said, is that “the parties themselves — Israelis and Palestinians — will negotiate a border that is different than the one that existed on June 4, 1967.”
“It is a well-known formula to all who have worked on this issue for a generation,” he continued. “It allows the parties themselves to account for the changes that have taken place over the last 44 years.”
Why did Obama talk about the 1967 borders publicly, to the chagrin of Israeli Prime Minister Netanyahu? Because in a rapidly changing Middle East, Israel, along with the U.S., stands to be further isolated if negotiations remain stalled–especially if the U.N. endorses Palestinian statehood in September. Regarding that prospect, Israeli defense minister Ehud Barak said, "We are facing a political-diplomatic tsunami. ...It is a very dangerous situation, one that requires action. Paralysis...will deepen the isolation of Israel." From that perspective, Netanyahu might view Obama's stance as an attempt to forge negotiations that will at least mitigate the tsunami. But there's little reason to believe that the prime minister will adopt that view.