Well it seems that actions has followed fairly quickly after Mr Bush's speech- US troops have raided the Iranian consulate in Irbil- this violation of diplomatic territory and consequently international law might be what Bush was referring to in part when he talked about political reasons for hanging back. Raiding consulates and embassies would definitely constitute such a move though he did suggest it was areas not particular buildings that would be subject to such politically dangerous raids, again the form of words could have been to throw enemies off the scent. The raids are very interesting- it strikes me that they demonstrate the confidence that the US has in Iranian involvement- they are a calculated risk as if embassy or consular staff were killed and later found to be unconnected to any illegal activity, the United States would be putting its own embassy and consular staff at risk in other countries.
Some conservative voices in the US are arguing that this doesn't go far enough and they'd like to see Iranian agents pursued across the Iranian border by US soldiers.
Its interesting as well that this happened in Irbil which is in the Kurdish region of Iraq- interesting for two reasons and I don't know which is right: either Kurdistan isn't as secure as we tend to think it is and the Iranians are destabilising it or Kurdistan is becoming a secure route into Iraq for Iranian smugglers. There is a third rationale of course which is that the Americans have just got it wrong- somethign that the Iranians no doubt would argue. We shall have to see.
2 minutes LATER
I should note that there is some argument about the status of the building raided- the Iranians claim it to have been their consulate however according to the BBC (whose report I linked to above),
sources at the US Pentagon said the building which was raided did not have any diplomatic status.
What this might lead one to beleive is that it was an informal Iranian diplomatic mission- maybe even a house associated with the Iranian mission- the Iranian and American language need not be in conflict. If it is and the building is unrelated to the Iranians then it obviously changes the nature of the comments that I made above.