1- you don't get something, Iran is having problems with its people, they are being pushed hard and may end up in a revolt. The government may have to kill a lot of people to put it down. They may start a war with say Iraq, which is really weak right now but that is only a deflection of the real internal issues they have.
2 - the people, even though don't like their government, will not tolerate an invasion or an attack. There is something about Iranians that make them one of the most patriotic people I have ever met. One explained it this way "we are the oldest country in the world and we are very proud of our heritage. Governments always change but the people do not." They may turn on the government quickly if the government attacks another country, like Iraq.
3 - the bigger threat is the UN because like other real serious issues, they will drag their feet and put obstacles in everyone's way to solve this issue.
4 - Russia can not afford to go to war, maybe you didn't notice but Russia seems to be holding it together by a few threads and overtones of the return of Communism are becoming louder by Putin and others within the government which has a lot of people there nervous. Given the nature of their relationship with the EU and with some of the former Soviet counties, it is highly unlikely that they will support Iran if something happens like Iran attacks Israel. OH and let's not forget that even if there are fanatical Muslims in Russia, there are a lot of fanatical Jews still there and they seems to be in a good position to cause a lot of problems for Russia.
5 - China may be the only real problem for us, but than again they may still enjoy the money.
