The conflict in Lebanon between Israel and Hezbollah had hardly begun when the Bush administration and its neoconservative supporters began blaming Iran for the conflagration. (...) However, giving Iran another tongue lashing, or worse, deciding to attack it, will do nothing to stop the violence in the region. Not only is there no evidence that Iran had a role in instigating this round of violence, the possibility itself is unlikely.
Iran’s control over Hezbollah has been steadily declining since approximately 1996, during the reformist presidency of Mohammad Khatami. Money does continue to come "from Iran" to support Hezbollah, but not the Iranian government. Instead, it's private religious foundations that direct the bulk of support, primarily to Hezbollah’s charitable activities. Nor are the amounts crucial to Hezbollah’s survival; even the high estimate frequently cited in the press—$200 million per annum—is a fraction of Hezbollah's operating funds.
While the Iranian central government was weak and scattered after the Revolution, semi-independent charitable organizations, called bonyad (literally, “foundation”) sponsored by individual Shi’ite clerics began to help the fledgling Hezbollah organization establish itself as a defense force to protect the Shi’ite community. This was simply not state support. Given the semi-independent corporate nature of Shi’ite clerics, especially in the early days of Iran’s revolution, when internal power struggles were endemic, there was little the Khomeini government could do to curtail these operations.
Now, after nearly two decades, this ad hoc export of Iranian revolutionary ideology may have succeeded too well. Whereas today the bulk of the Iranian population has at least some doubts about their government, Hezbollah maintains a stronger commitment to the symbolic legacy of the Iranian Revolution than Iranians, according to Georgetown University professor Daniel Byman. In a 2003 Foreign Affairs article, Byman pointed out that, "[Iran] lacks the means to force a significant change in the [Hezbollah] movement and its goals. It has no real presence on the ground in Lebanon and a call to disarm or cease resistance would likely cause Hezbollah's leadership, or at least its most militant elements, simply to sever ties with Tehran's leadership."
William O. Beeman, Examining Iran’s ties to Hezbollah