Something that pro–US involvement pundits don't talk about:

Iran's deterrence strategy relies on being a "hedgehog" for lack of a better term.

Hedgehogs aren't predators.
They can be taken down but not easily.
And the predator will come out of the fight in massive pain.

Roughly, IR's hierarchy of priorities:

1. Maintain the nuclear and missile programs (in that order)

2. Ensure regime survival

3. Inflict max pain

– (1) isn’t existential yet.
– Advocates for US involvement and the IR opposition think (2) is already under threat. (I disagree obviously.)
– But if Iran does feel existentially threatened, it’ll activate (3).

Max pain will look like:

1. Guerilla warfare from within the borders.
Think Iraq’s Shia militias but x10.
This'll prevent any boots on the ground to 'finish the job' and will reach out of the borders to inflict pain.

2. Closing the Strait of Hormuz.
Massive oil shock. It'll last way than people currently expect.
This'll be naval guerilla warfare in the drone age. Basically, Iraqi Shia insurgents meets Ukraine-style drones, but at sea.
This is mainly unimaginable today the same way guerilla warfare in Iraq wasn't a concern during the invasion or even the first phase of that war.

3. Drones and ballistic hell across the region.
Israel’s Iron Dome level of defense is only sustainable short-term — and that level of defense doesn’t exist anywhere else in the region. On the other hand, the IR stock pile isn't infinite and won't be replenishable if we get to this stage. Still doesn't mean this'll be easy.

The max pain phase will drag far longer than the collapse of the regime if that ever comes. 
This is why it doesn't seem to me that "regime change" is a viability -- it'll just be *regime collapse* and max pain.

Disclaimer:
Putting this out because I don’t see it being discussed. It's not a statement of preference, just how I think the deterrence logic plays out from an IR perspective.

Trump has reviewed attack plans for Iran but is holding off to see if Tehran steps back from its nuclear program, a person familiar with the matter told CNN.

Israeli Prime Minister Benjamin Netanyahu thanked Trump for “standing by our side” as Israel pushes ahead with its fight against Iran.