Glenn Greenwald has a detailed analysis of Joe Lieberman's Op/Ed in which he comes close to calling for war against Iran. Greenwald goes on to provide the recent history of U.S.-Iranian relations:
Back in late 2001 and early 2002, U.S.-Iranian relations were at their best state, by far, since the 1979 Islamic Revolution. The two countries were cooperating extensively in Afghanistan. New diplomatic channels had been created. Iran was eager to make one concession after the next in order to achieve rapprochement with the U.S. And foreign policy experts including Colin Powell were hailing the prospects for a new cooperative relationship with the Iranians.
By the end of January, 2002, David Frum wrote George Bush's State of the Union speech declaring Iran to be a charter member of the "Axis of Evil," and relations between the two countries have been quite hostile ever since. Even after that occurred, the Iranians continued to make extraordinary overtures to better relations, but they were all unceremoniously rejected by the Bush administration.
Greenwald skips over a key point here, perhaps because he assumes his audiences is keenly aware of it. Perhaps our Senators are not. Iran is a Shiite nation. Iran cooperated in Afghanistan, in part, because we were ousting the Sunni Taliban -- a government Iran had opposed for years. Iran is not in league with al Qaeda, which is a Sunni group. To the extent that Iran is responsible for violence in Iraq, it is by virtue of supporting Shiite groups who are attacking the Sunni minority, which could include members of al Qaeda.