Israel has threatened attacks on Iran that have concerned some people in the past, but now it is seen as an obvious bluff. China will not allow it's primary source of oil to be disrupted. No doubt they have conveyed this to the American government. There is little Israel can do at this point except to huff and puff. This is primarily for their audience in Israel. Everybody else sees it for what it is.
Israeli ambassador to U.K.: Elements of left 'in denial' about 'disease' of anti-Semitism (Haaretz)
from the article: Ahmadinejad unveils three new Iran nuclear projects