Both timelines for both Israel and the US are predicated on "if" Iran does something. There is no evidence at hand that Iran is developing nuclear weapons according to the UN inspectors. But that is irrelevant--USIsrael want regime change. Period. The nuclear argument is a pretext.
UN Syria envoy begins Russia talks, says wants partial truce revived (Reuters)
from the article: Israel and U.S. at odds over timetables and red lines for Iran