As Donald Trump considers a possible ground operation, Iran’s layered military structure is emerging as a major challenge for U.S. forces. Beyond the well-known Quds Force, Tehran relies on a network of elite and semi-regular units like Saberin teams, Basij fighters and airborne NOHED forces. These units are designed for rapid, distributed response across land and sea, making any invasion far more complex than expected. Experts say this system allows Iran to react instantly and overwhelm landing zones. If conflict escalates, U.S. troops may face not one force, but an entire coordinated battlefield.