As they got Hussein out of some stinking gutter hole in Bagdad where he tride to hide
Iraq and Iran are in different weight categories.
Iraq has a population of 45 million people, and this is up from a population of 27 million people in 2003 - when the Americans invaded.
Then, Iran already had a population of 68 million people. Today Iran has a population of 90 million people.
Iraq is 400K sq km, and Iran is 1.6M sq km. Iraq is flat and composed largely of desert. Iran is mountainous, like Afghanistan.
Iraq is roughly 60/40 Shia and Sunni. Iran is 90/10 Shia and Sunni - that is, much more homogenous and less divided.
Iraq produces nothing but oil and gas, while Iran manages to produce cars, pharmaceuticals, construction materials, and also - surprise - sophisticated missiles.
Iraq is a fake country invented by Britain in the 20th century. Iran is one of the foundational civilizations in the world, with more than 4,000 years of history. Only the Egyptians and the Chinese might claim to be as ancient.
Bottom line - Iran has a bigger population than Germany, a bigger military than anyone in Europe, and a very difficult terrain - similarly to Afghanistan. Unlike Afghanistan, they sit on some of the world's largest oil and gas reserves, and have a very educated population.
America alone mobilized half a million men for the invasion of Iraq. How many soldiers must be prepared for the invasion of Iran then?