While I wouldn’t like it I think the US should keep a permanent Brigade or Division with a port in Iraq. I expect we’re going to need troops on the ground in that area again and it’d be better to already have an established presence.
The permanent stationing of a Heavy Brigade would be a challenge. The port (and Iraq only has one that can be charitably described as modern) would need upgrades in security and infrastructure, the Lines of Communication (LOC’s) would need built and secured.
The Brigade would require a huge terrain footprint (if you consolidate at one location): expensive and a big target, or disburse the sub-units on smaller bases spread out: more expensive and lots of smaller targets. The Brigade would have to defend those bases and/or conduct security operations “outside the wire”. It can be ordered to do both, but will likely fail at one which will leave significant vulnerability at the other.
A model for this type of operation might be the planned stationing of a Brigade+ in Poland. Expensive (though the Poles are paying quite a bit) time consuming, and personnel heavy, and this is in a “permissive” environment. If we have to do it in Iraq now, we will have to defend every pier, highway/airfield and base from zombies who hate us and see us as “puppets of the Jews”. If we had to move the Brigade somewhere else, we’d likely have to fight our way out, and be back filled by another Brigade, or watch our base be overrun and looted. (see “withdrawal from Afghanistan”). This is just a SWAG, your mileage may vary... Cheers!