Now that it is confirmed that the US indeed did kill Qassem Soleimani, the head of Iran’s Quds Force and effectively the second most important person in Iran, responsible for the deaths of untold numbers of civilians and many US troops, here are some thoughts.
Most responses are that this will start a major new war or at least a major escalation with Iran's terrorist proxies targeting US leaders.
First of all, the so-called experts have been wrong every single time they predicted a major response from things Trump decided to do. The "experts" simply aren't.
My guess is that Iran will instruct Hezbollah and Islamic Jihad to shoot rockets into Israel, even though there is no evidence that Israel had anything to do with this (excellent intel, by the way.) This is a face-saving routine and Iran still clings to the idea that escalating things with Israel will get the Muslim world on their side. That isn't true anymore, but this might be Iran's thinking. (Israel closed the ski resort in Mount Hermon anticipating this very scenario.)
Not only Soleimani was killed - also Abu Mahdi al-Muhandis, the deputy commander of Iran-backed militias Popular Mobilization Forces, and reportedly Naeem Qasm, Hezbollah's #2 in Lebanon. You have to think that the remaining leaders of Iranian forces and proxy forces are very frightened of being killed themselves. If they escalate, that is a death sentence. I don't think they are that brave.
Furthermore, Soleimani was widely considered a genius in his military and terror activities. He was the one who would have decided on a calibrated response. Whoever is replacing him will probably err on the side of conservatism, because the US is now considered unpredictable - previous administrations would never have done anything like this.
In addition, Iran is hurting from economic sanctions that has already been weakening Iran's military. It seems likely that this attack will embolden Iran's protesters to redouble their efforts, which will strain Iran's military even more. The same thing seems to already be happening in Iraq with protesters against Iranian influence celebrating.
I cannot see the Revolutionary Guards' morale remaining high with the loss of their powerful leader and their countrymen, probably, celebrating.
I do expect a response - Iran is still an honor/shame society and some action, now that the US admitted its role, is deemed necessary. But I think it will be a limited response. Perhaps cyberattacks, perhaps rockets to Israel as I mentioned, perhaps some directed attacks at US troops in Iraq or a 1983 Beirut-style attack against US military installations in Europe.
Today, lots of very dangerous people are very scared. Hezbollah leader Nasrallah is going deeper underground than he already was. Maybe even Kim Jong-Un.
There may be - hell, there will probably be - some unintended consequences. But they happen all the time anyway. The precipitating event is by any measure a very good thing, because nothing could weaken Iran in one blow as much as this attack.
Today, Iran's military is significantly weaker in Iraq, in Lebanon and in Iran itself. Rarely can a single attack affect so much in such a positive way. There will probably be blowback, but it is hard to see how that will help Iran recoup its losses. Iranian leaders want to cling to power above all, and extended global adventures do not help that goal when the regime is already weakened.
It is not a symbolic loss for Iran. It is a major, major blow, and one that might be a permanent and serious wound for the regime itself.