According to a December 2017 Rand Corp.
, a major conflict with Iran would require the U.S. to deploy 21 Air Force fighter squadrons, five heavy bomber squadrons, six Marine Corps fighter squadrons, 18 attack submarines, four aircraft carriers, a suite of intelligence, surveillance, and reconnaissance vehicles, six Marine infantry battalions, three Army brigade combat teams, and a crowd of special operations forces — not to mention a host of drones, satellites, cruisers, counter-mine vessels, supply ships, refueling aircraft, and surface-to-air batteries. Put another way, a war with Iran would require the U.S. Air Force (for example), to deploy nearly half of its fighter squadrons (there are 55 in all) to a single conflict. It could do it, but just barely. What is being assembled is barely enough for a war with Iran. It’s likely Trump is trying to pressure Iran. Or they are underestimating Iran setting themselves up for a catastrophic fiasco if war breaks out.