This article from open democracy gives an important and comprehensive analysis of the Iranian situation. For me Iran is a cornerstone for the development of the entire middle east. If the theocratic dictatorship i Iran finally has to admit its failure and will be overtaken by a civil democratic society, fundamentalist islam will loose its attractiveness. If the biggest and richest islam country in near east steps away from religious fundamentalism, then it will survive only in pockets of desperate poverty.
Putting down the regime in Teheran is one of the priorities to secure freedom and progress in our world. But only the people of Iran can do this. Any military intervention would only help the regime. As the article in "open democracy" shows, it could be assumed that the regime is searching for a military intervention to regain popular support.
All what the west can do is to get Iranians richer and inclose them into the international society instead of isolating them. Religious fundamentalism does not survive economic development and globalization. Clearly this does not mean to accept any outrageous action of the regime, but it means to keep in mind the principle.