'The US would not contemplate military action unless Iran actually tested a weapon?'

"... The problem for Netanyahu is that the Obama administration does not view Iran — even an Iran with nuclear weapons — as an existential threat that is worth starting another war.....  Obama decried what he called the “loose talk” of war and spoke eloquently of the costs of military conflict for a nation that has fought two wars in the last decade. The “most searing” moments of his presidency, he said, had come when meeting the relatives of Americans killed and injured in Iraq and Afghanistan.....
Obama also refrained from using the phrase “nuclear weapons capability” and spoke only of actual nuclear weapons. That suggests that the U.S. would not contemplate military action unless Iran actually tested a weapon. Israel wants to act much earlier but lacks the resources to do as much damage as the United States could do....
A recent report^[3] by Anthony Cordesman and Alexander Wilner for the Center for Strategic and International Studies notes that Israel, which has at least 100 nuclear weapons, poses an existential threat to Iran since it could destroy “five to seven major Iranian cities.” Israel also has three ways of delivering a nuclear bomb: by missile, submarine or plane.
Iran insists it does not intend to make weapons; the Obama administration says that Iran does not appear to have made the decision to build or test a bomb....
With US political polls shifting increasingly toward Obama as the Republican nomination fight drags on, Netanyahu may also calculate that a bigger and more immediate threat to Israel would be to alienate an administration that looks increasingly likely to govern the United States for the next four years."