From ABC News:
Beyond the obvious conflagration of war that bombing the nuclear facility at Qom would likely ignite, senior administration officials are saying military action could be counterproductive in two other ways.
One: The goal of the U.S. government is not to close this one facility at Qom, but rather to convince the Iranian government to end their nuclear weapons ambitions writ large.
Second: Bombing the facility might only make the Iranians more determined, whereas if Western intelligence agencies catch them violating their agreements every time they cheat -- and this is the third time since 2002 -- the Iranians may conclude, ultimately, that any aspirations for a nuclear weapon are futile.
Read more ....
Update: US military action against Iran would only 'buy time': Gates -- Zeenews
My Comment: Both articles give a convincing argument on why the US will not strike against Iran's nuclear facilities. They (naturally) omit what the Israelis may end up doing.