What the US wants in Iran and Syria is regime change. To make way for US dominance of the Middle East, nationalist and militant Islamic regimes have to go. It's true that the prohibition against Islamic regimes is not dosolute, for example le US might be prepared to do business with the ultra-conservative Muslim Brotherhood in Egypt and countenance them being part of government, just as the Supreme Council for the Islamic Revolution (SICRI) is in reality a decisive part of the government in lraq.
But the Iranian regime is another matter, seen as more or less openly backing the spread of radical Islam, and giving open support to Hizbollah in Lebanon, lining up with the Syrian government and backing anti-Israel movements everywhere.
The campaign against Iran over nuclear technology is part of the campaign for regime change.
Probably the US doesn't really believe Iran is building a nuclear bomb at all. In the speculation about the costs to the US of a military strike on Iran, many commentators seem to underesStates has been to using the military option - a strike against Iran's nuclear facilities which would cost hundreds of lives.
Equally Syria, seen as backing insurgent forces in Iraq, has been close to some form of military attack, with US troops crossing over the border from Iraq in 2005 in 'hot pursuit' of Iraqi insurgents.
For the time being the US has made concessions to the European states in not extending the military option outside of Afghanistan and Iraq. When Tony Blair flew to meet Angela Merkel in Berlin last month, the main topic was indeed Iran and how to put forward an alternative to military action. But there is no absolute decision on the part of the US not to resort to military action against Iran and Syria.
However it is true that in addition to the views of the Europeans, there is concern in Washington about the consequences of an Iran attack in Iraq. And this points to the strategic brittleness and failures of the whole Iraq war operation.
Once the US decided on the Middle East as key arena for its military operations, then it opened up the possibility of political defeat in the region with enormous consequences. For the US that just cannot happen; it would capsize its world order plans, allow the Europeans back into the Middle East as a major economic and political force and be a body blow to armed globalisation under US dominance.
The US has no choice but to plough on in the region.