Although slight differences in some of the players may manifest themselves (I have concerns over the steadfastness of our dear British Friends. I have the feeling that public sentiment there would not permit another major engagement. PM Blair has been AMAZING during this difficult time, but would his successor be made of the same strong stuff?) I find it hard to quarrel with your scenario.
However, if Iran is to be engaged, then Russia, China, Syria, North Korea and others may decide to lend them a hand. Anti-Semitism has become breathtakingly rampant throughout much of Europe and Asia, and a hot conflict with Iran will be perceived by many as being a matter of "Zionist agression" against Islam. Nations that have been covertly and overtly working against not only Israel but the USA may decide that this is their chance to rid the world of two problems in one motion.
Bottom line: Unless the USA or another Western nation suffers another major terror attack, I am doubtful that we will be able to find sufficient support in our own country as well as abroad for taking out Iran's nuke program by force.
I envision endless, useless talk until Iran launches a nuke at Tel Aviv.
I hope and pray that I am completely wrong.
I really believe Israel would force this issue to a conclusion well before any nukes are launched at Tel Aviv. Generally people at FR are overestimating the military capability of Iran, and that goes for the two-bit dictators in North Korea, Syria, etc. Iran couldn't do much of anything to our troops in Iraq. If they ventured over the border they would be routed very quickly by superior air power and ground firepower. Sure it won't be easy to build support for action against Iran, but inaction is not an acceptable course of action. Inaction creates the scenario of a likely nuclear sneak attack against the US, Britain, or Israel, and that scenario is completely unacceptable to the leaders of those three countries.