Iran's missile strikes against bases in Iraq housing US troops was not a response designed to kill the most Americans possible.

Iran will have known that in the early hours of the morning, US troops are normally asleep and the chances of inflicting casualties are lower.

Iran will also have known the US has a strong air defense that would likely have been on high alert. Tehran should have a grasp of how well its missiles would fare against such technology.

Iran strikes Iraqi bases housing US troops. Map: CNN

The missile attacks don't make sense if Tehran's goal was to really hurt US troops in large numbers -- like some had been pledging to do. They do make sense however as the execution of Supreme Leader Khamenei's order to strike back openly against US military targets in response to the killing of Iranian general Qasem Soleimani.

Khamenei's instruction was confusing when first reported, as the US is bound to prevail in a straight military-to-military conflict. Was the Supreme Leader ordering an empty show of force?

The dust is still settling, and even at the best of times Iran's motivations can be opaque, but there are three possible explanations for the action.

First, that Khamenei is out of touch with what his military can achieve and overestimated the effectiveness of the strikes, which then failed. This would be surprising given his reported involvement in and knowledge of Iranian military affairs.

Second, that moderation won out, and this largely empty signal -- hitting military targets in the dead of night with a small number of missiles -- provides the off-ramp both sides might ultimately want. This would be logical, given neither Tehran nor Washington have much to gain from a prolonged fight.

Third, this might be a bid by Iran to put the US into a false sense of security -- that Iran is militarily weak and has done its worse -- while an asymmetrical and nastier response is brewed. That would require a lot of strategic acumen from a government split between hardline and moderate wings, and means Tehran was relatively assured no Americans would be hurt in this missile attack.

If the attacks in Iraq are indeed the full scope of Iran's response, they carry with them another risk: that the Trump administration think their ramshackle performance over the last week has paid off, and Iran has been vanquished. This would risk further irrational action from Washington, perhaps not just against Iran but also other enemies. It also makes Iran look weak, which may embolden Tehran's other regional adversaries.

Iran's response to the killing of Soleimani was always going to be difficult to predict. But -- if the strikes truly are the entirety of Tehran's revenge -- few would have anticipated something so swift and so openly military-to-military.