Because you lose control

Gareth Porter on the Democrats' unwillingness to rule out military force in Iran:

These Democrats act as though their support for keeping the military option alive—as opposed to supporting an actual attack on Iran—carries no risk, but that notion represents a profound misunderstanding of what it means to threaten aggressive war against Iran. In fact, keeping that threat “on the table” carries three very serious risks.

A war with Iran could be triggered by accidental or deliberate U.S. military provocation. To make the threat to Iran credible, the administration is deploying carrier task forces to the Persian Gulf, which inherently increases the likelihood that some U.S. naval commander will fire unnecessarily on an Iranian ship or plane. That is exactly what happened in 1988 when the cruiser USS Vincennes—apparently thanks to the aggressive tactics of its commander—shot down Iran Air Flight 655. That danger is especially acute given the provocative nature of the Bush administration's policy toward Iran.

Alternately, the administration may pursue a carefully calibrated strategy of combining a military buildup with increasingly warlike rhetoric, only to find that it has made Iran less, not more, willing to compromise. Even assuming that the White House has made no decision to attack Iran now, such a decision becomes far more likely once coercive diplomacy has been pursued and has failed.

Even if we are fortunate enough to dodge both of those bullets, coercive diplomacy carries the risk of tilting the political balance within Iran toward the actual manufacture of nuclear weapons. Contrary to the official Bush administration line, U.S. intelligence has long held that Iran’s policy toward the pursuit of nuclear weapons is significantly influenced by the U.S.'s policy toward Iran’s security concerns.

Using inflammatory language -- like "we've got to keep all options on the table" -- is only useful if one of the things you want is to inflame the situation. I have no explanation for why this seems to elude people.

Let's put it this way: even if Ahmedinejad weren't nutty and Bush weren't totally hopeless, and you still had two perfectly rational actors at work here, it's impossible for either side to trust the words of the other because each side keeps saying different things. If I'm the leader of Iran, and one day Cheney says an attack is possible/necessary, but the next day Bush says there's no attack planned, what do I do? Plan for the worse, obviously. The idea of indulging in the optimistic outlook -- that Cheney is freelancing and Bush doesn't want a war -- is discounted.

For a perfect example of how these dynamics occur, just take a look at, oh, absolutely every interpretation of Iranian actions for the last 2 years or so. Ahmedinejad's rhetoric gets all the press, but more mollifying words from the Ayatollahs get ignored.

As a side note, does anyone find it amusing that the Iranian Presidency used to be considered so powerless that when it was held by a reformer the US still couldn't talk with Tehran, but now that it's held by a firebrand it's so powerful we might need to get our war on? I think the people of Iran have noticed.

Increasingly, a lot of secular Iranians, like myself, are figuring that even if Iran is turned into the most democratic, secular, fair and peaceful state on earth, there is no guarantee the US won't find another excuse to try to overthrow its goverment. It will start bullying Iran for its "devastating role" in climate change, or animal rights, or - who knows? - for obesity.