One reaps what one sows

Suppose it's true that Iran is not only arming Shiite militias in Iraq but also the Taliban in Afghanistan (but maybe it's not). Before we leap to the conclusion that the U.S. must retaliate military, as Joe Lieberman has argued, consider Seymour Hersh's article from two years ago that claimed that the U.S. had sent commando teams into Iran to assist in targeting in the event of U.S. airstrikes on Iran, and to support various separatist movements in Iran. And the threats this action provoked from Iran, according to Asia Times:

TEHRAN (April 25, 2006) - A former Iranian ambassador and Islamic Republic insider has provided intriguing details to Asia Times Online about US covert operations inside Iran aimed at destabilizing the country and toppling the regime - or preparing for an American attack.

"The Iranian government knows and is aware of such infiltration. It means that the Iranian government has identified them [the covert operatives] but for some reason does not want to show [this]," said the former diplomat on condition of anonymity.

Speaking in Tehran, the ex-Foreign Ministry official said the agents being used by the US "were originally Iranians and not Americans" possibly recruited in the United States or through US embassies in Dubai and Ankara. He also warned that such actions will engender "some reactions".

"Both sides will certainly do something," he said in a reference to Iran's capability to stir trouble up in neighboring Iraq and Afghanistan for the occupying US troops there.