Well, this is a tough question to answer without knowing the status of your world, but here's one possible scenario:
1) Someone your players care about finds themselves in the Middle East. Details are up for grabs here; perhaps she was with the Red Cross in Afghanistan, or on a business trip, or visiting relatives, or was kidnapped and dragged there. Somewhere along the line she disappears.
2) The players hear on the news that Iran has announced the capture of an American (or Israeli) spy trying to cross their border. (This should sound a bit familiar.) The players should be certain that the charges are bogus.
3) Give the players some time to consider this. If they hold off on acting, then some time later they learn that the Iranians have announced that the spy was found guilty by their eminently impartial courts, and will be executed in two weeks. American officials raise an outcry in the UN, but nothing comes of it.
4) Optionally, throw in a foiled attempt by the CIA and/or special forces to rescue the individual. Perhaps several of the rescue team are killed, and several more are held along with the original 'spy' to be executed once the trial is held.
5) If the players still stall, have a mutual friend beg for help. Or possibly an old enemy gloating that they set this all up, and that there's nothing -- NOTHING -- that the players can do to prevent the death of their loved one! (Muahahaha!)
6) Assuming that at some point in the above process the players decide to act, run them through the rescue. Make it harrowing, etc. Most likely, they will win through ... and in the process, will accidentally (or not so accidentally) kill one or more Iranian officials. Maybe an Imam or two who were involved in the questioning, or El Presidente For Life. They may not even know the significance until later.
7) Safe at home, they consider the issue closed. Until ...
EIGHT) (Because you can't use the number with a right paren, it turns out) News rocks the world that several nuclear blasts have occured nearly simultaneously in Tel Aviv and Tehran. Lots of confusion at first, but eventually pieces are put together to reveal that Iran launched a newly developed missile at Israel, claiming that Israel was behind the heinous assassination of the above-mentioned official(s), and that the strike was in response to this act of war. In the minutes the missile was in flight, Israel launched their own retaliation.
9) America, while refusing to commit nuclear assets immediately, announces that:
a) Any further use of WMDs will result in the total anhilation of the country launching them
b) That the U.S. has declared war on Iran for their first-strike use of WMDs and that the U.S. carrier force in the Gulf has already begun conventional bombing of key sites in Iran
10) <Insert foreign powers here, perhaps China/Russia, or even the EU>, while condeming both Iranian and Israeli use of WMDs, strongly condems the U.S. reaction, and demands that all aggressive actions cease immediately or suffer the consequences...
Etc.
