They probably don't want to be lectured by Obama about how dangerous it is to bomb Iran. I'm sure Bibi has heard it all - and often.
The problem is, Israel should realize that America is going to be blamed anyway, even if we don't participate in an attack. In that case, they owe us the courtesy of giving us a heads up if they intend to take out the Iranian nuclear program.
Leon Panetta, the US defence secretary, flew into Israel last month on what was ostensibly a routine trip.
Officially, his brief was restricted to the Middle East peace process, but the most important part of his mission was a private meeting with Mr Netanyahu and the defence minister, Ehud Barak. Once all but a handful of trusted staff had left the room, Mr Panetta conveyed an urgent message from Barack Obama. The president, Mr Panetta said, wanted an unshakable guarantee that Israel would not carry out a unilateral military strike against Iran's nuclear installations without first seeking Washington's clearance.
The two Israelis were notably evasive in their response, according to sources both in Israel and the United States.
"They did not suggest that military action was being planned or was imminent, but neither did they give any assurances that Israel would first seek Washington's permission, or even inform the White House in advance that a mission was underway," one said.
Alarmed by Mr Netanyahu's noncommittal response, Mr Obama reportedly ordered the US intelligence services to step up monitoring of Israel to glean clues of its intentions.
Nothing is expected to happen until Spring or Summer of next year given the difficulties of bombing during the winter months. But you can be sure that the US will be monitoring Israel's air force and Obama just might warn Israel publicly about an attack, thus giving the Iranians advance warning.