Iran is 557,648 (sq km) larger in land area than Iraq & Afghanistan combined Iranian population is 13,033,072 greater than Iraq & Afghanistan combined
The cost of the Afghanistan and Iraq wars since 2001 – $1,377,731,216,088 (http://costofwar.com/)
Iran – 1,648,195 (sq km) / population: 76,783,000
Afghanistan – 652,230 (sq km) / population: 30,419,928
Iraq – 438,317 (sq km) / population: 33,330,000
Afghanistan and Iraq combined land area – 1,090,547 (sq km)
Afghanistan and Iraq combined population – 63,749,928
Even in order to fulfill the stated objective of ensuring that Iran never acquires a nuclear bomb, the U.S. would need to conduct a significantly expanded air and sea war over a prolonged period of time, likely several years.
If the U.S. decided to seek a more ambitious objective, such as regime change in Iran or undermining Iran’s influence in the region, then an even greater commitment of force would be rquired to ocuupy all of part of the country.
Given Iran’s large size and population, and the strength of Iranian nationalism, we estimate that the occupation of Iran would require a commitment of resources and personnel greater than what the U.S. has expended over the past 10 years in the Iraq and Afghanistan wars combined.
The more ambitious the objectives of military action and the longer the conflict goes on, the more difficult it would be to design an effective exit strategy.