Here is a hypothetical but likely scenario for the war, if it happens:
1. The USN will stay way out of the range of Iran's AshBMs initially.
2. The USAF and the IAF will bomb Iranian missile sites and OTH radars in the opening hour of the war aggressively. They will also assassinate top commanders of Iranian forces, particularly the IRGC.
3. After Iran's OTH radars and missile sites have been neutralized, the USN will get close to Iranian shores to strike the remaining targets using cruise missiles, particularly the police, Basij and anti-riot forces.
In the meantime, Kurdish and Baluch separatists will start attacking Iranian border cities while the remaining anti-IR forces in Tehran, Isfahan, Shiraz and other major cities will attack police stations and strategic targets like the IRIB, the parliament, the airports, etc.
This way the US will incur minimal casualties and Trump will be able to save face by saying that he did take care of Iran's BM threat and helped Iranians.