Would the US attack Iran?

The situation in Iran is really confusing. Mr Ahmadinejad, the President, in his most recent interview, is quoted as saying that “ I have no worries about the future of Iran. Why should I be concerned?”
In another part of his interview, he said, “the Americans are not in a position to attack Iran. They wish to put pressure on Iran and cause problems for us, but, they would fail”.
His foreign minister, Mr Mottaki, however informed the Iranian MP’s that “the American threat is serious and far from being just a psychological warfare and propaganda”. Mr Rafsanjani has added a new dimension by saying that in a recent meeting with Mr Khameneh-ee, someone said that the threat was not serious, but, the leader added, “No, you are wrong, the threat is serious indeed”.
I tend to share this view that Mr Ahmadinejad is wrong here. His reasoning is simply dangerous, i.e. saying that the Americans are bogged down in Iraq, hence, would not attack is a dangerous oversimplification. As a matter of fact, following his own reasoning, for that very reason, it is potentially feasible that in order to divert attention from the mess in Iraq, the American administration may decide to open a new front by attacking Iran.
This said, I hope that I am wrong and the issue would be settled through diplomacy and negotiation.