Non-military alternatives against nuclear Iran do have the potential for success. I believe it is best to try non-military actions first because innocent people will not be killed. There are many groups working toward non-military solutions and collaborating for peaceful resolutions. United Nations inspectors can search for nuclear materials and politicians can continue to negotiate with iran.
Non-military action can never be ruled out unless it has first been tried. Wars have been stopped before from civil discussion and compromise, and Iran is no exception. Countries also take umbrage against the US having nuclear weapons but they do not use military force to extract them from the country.