Although I think it's likely that America will attack Iran I think it's very unfortunate and that there are many better options. Ironically, America may be forced to deal with Iran militarily because we will probably be unable to convince our "allies" to participate sufficiently to make less violent solutions viable.
For example, Representative Steve Israel has written an article arguing that restricting Iran's import of gasoline would convince the mullahs to drop their nuclear program.
Still, there is one option to consider before resorting to war. Iran may be a major exporter of oil, but it imports 40 percent of its gasoline because it has a limited refining capacity. And like us, its population is sensitive to the price of gas in an uncertain economy.
If diplomatic, economic and other tools don't work in dissuading the Iranian regime from its nuclear ambitions, reducing the amount of gas that goes into Iran may. Doing so would dramatically increase the cost of gasoline in Iran and put political pressure on the government to rethink its nuclear program and isolation in the world. A global commitment to keeping gas out of Iran is more effective and manageable than keeping oil in.
Such a strategy could possibly be effective, if the rest of the world was willing to agree. However, this is exactly the sort of solution that would require consensus from Russia and whatever other countries refine Iran's oil into gasoline. America couldn't enforce such an embargo alone unless we were willing to use military force to disrupt pipelines over land and disrupt shipping overseas. Attacking a foreign ship at sea is an act of war, so unless we get, for example, Russia to agree to stop refining oil for Iran then we simple exchange a war with Iran for a war with Russia. Not a good trade.
The only effective action that America can take on its own, without using our military against countries other than Iran, is to attack Iran itself. Given the near-certainty that the UN its various kleptocrat members will refuse to enforce substantial sanctions against Iran, we'll end up being forced into the military option by our reluctant "allies".
It's worth remembering that countries don't have allies, they have interests. We'll work with anyone else whose interests coincide with ours; anyone who claims to be an ally but who has different interests is only making the claim to hinder us and help themselves.