According to a December 2017 Rand Corp.
report, 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.
“We’ve been in the air and in combat since 1993,” a senior retired Air Force officer said, “and the wear and tear on the force has been considerable. The tempo has been crushing.” This claim is actually an understatement: Nearly 30 percent of Air Force aircraft are not “mission capable,” the service is experiencing a shortfall in experienced pilots by some 2,000, and maintenance crew capabilities have
deteriorated. And what is true for the Air Force is true for the other services. In 2016, Army Vice Chief of Staff Daniel Allyn conceded that only one-third of his force is at “acceptable levels of readiness,” and in January of this year, a group of influential Navy officers expressed
fears at an American Enterprise Institute war game that “the combination of constant commitments and diminishing resources” may well have left the Navy “too small, too old, and too tired” to carry out its mission requirements, according to a write-up of the event. Meanwhile, in 2016, Marine Gen. John Paxton
reported that half of all U.S. Marine units were “suffering from some degree of personnel, equipment, or training shortfalls.”