If the goal is to overthrow the regime by force, you need boots on the ground. The basic approach might be something like the Iraq war but bigger, and with an actual plan for the aftermath. And it might end up being the biggest (or at least the most intense) war the US has fought since WW2.
Air strikes are effective at killing people and destroying property, but their impact on the situation on the ground is limited. Even if you manage to destroy the regime, there needs to be an alternative with sufficient legitimacy and institutional support to replace it. But authoritarian regimes are pretty good at keeping the opposition weak and fragmented, making such alternatives unlikely to emerge. So you either need occupying forces to provide the institutional support, or the likely outcome is a civil war.
> If the goal is to overthrow the regime by force, you need boots on the ground.
You have the Artesh in Iran, their standard military which is bigger than the IRGC and aren't under Islamist rule and they are loyal more to the democratically elected government than the Islamist one.
> But authoritarian regimes are pretty good at keeping the opposition weak and fragmented, making such alternatives unlikely to emerge.
They never destroyed the Artesh, that army has been the same since before the 1979 revolution, so your analysis is wrong for Iran since they do have those power structures in place. If you destroy IRGC the rest of Iran would run just fine. They have elections, they have a democratically elected government of reformists who want to move away from Islamist rule, those elected politicians however don't have the power to do that currently but if you shift the power enough it could happen.
Destroying the regime is much easier than destroying the IRGC. The former requires killing enough key people and destroying enough key infrastructure to make the regime unable to govern and take initiative. The latter requires killing most of the people with the weapons and ideological commitment to continue fighting. If you do the latter, the country will not be in a state where it can hold democratic elections.
The Gaza war is a good example. Israel quickly reduced Hamas to a mostly reactive resistance force. But it was unable to destroy Hamas as a relevant force.
As for the standard military, authoritarian regimes are also keenly aware of the threat posed by the military. That's why they have large internal security forces, such as the IRGC. Common practices to mitigate the threat include promoting harmless unambitious people to leadership positions and trying to keep the ranks free of people with strong ideological commitments. While the standard military outnumbers the internal security forces, it tends to consist of people willing to serve the regime and choose the status quo over a civil war.
> Destroying the regime is much easier than destroying the IRGC.
IRGC is an oil money empire, they aren't ideological warriors they are mercenaries that fight for money, remove the oil and the empire crumbles. Its like removing ad revenue from Google, it would destroy the company and what is left would be a small husk of its former self.
So blocking the oil will massively weaken IRGC and keep Artesh the same, since Artesh is made up of people who actually want to fight for the country.
Sure they have some nice statements about ideology and saving the world etc on top, but the main driver is the money.
Ideological commitment and personal beliefs are orthogonal, much in the same way as religion and personal faith are orthogonal. IRGC members are ideologically committed, because they have chosen to serve the regime. They are committed, because if the regime ever fails, things will be bad to them personally.
Authoritarian regimes also understand that they need to keep their core supporters happy. If oil money dries up, everyone else will suffer before the IRGC. See North Korea for an example.
> If oil money dries up, everyone else will suffer before the IRGC. See North Korea for an example.
90% of IRGC funding comes directly from their own oil empire, without oil they barely have any funding. They can't make the other parts suffer before themselves here since they get it directly from owning the oil exports, it doesn't go via the government.
If they start trying to take money from the military then they would start the civil war themselves, they can't do that.
Assuming the goal is 'Advance American interests'... Not tearing up the nuclear deal. Instead, soft and hard power should have been used to leverage compliance with it.
Instead, of course, he tore it up in exchange for... Nothing.
Well, not nothing, Israel likes to have an excuse to bomb Iran whenever Bibi needs an excuse to stay out of prison.
Air strikes are effective at killing people and destroying property, but their impact on the situation on the ground is limited. Even if you manage to destroy the regime, there needs to be an alternative with sufficient legitimacy and institutional support to replace it. But authoritarian regimes are pretty good at keeping the opposition weak and fragmented, making such alternatives unlikely to emerge. So you either need occupying forces to provide the institutional support, or the likely outcome is a civil war.