http://forums.spacebattles.com/threads/least-competent-national-military-force-of-the-20th-century.117762/page-2#post-3170537 said:
The Iranians were outnumbered for most of the war. Often badly. While Iran had a larger population with a larger draft pool, the problem was the Iranian logistic system totally collapsed after the revolution and was never rebuilt. As a result the Iranians could rarely keep more than 400,000 troops in the field, while the Iraqis routinely had 600-800,000 men.
And the Iraqis were much better armed too. By the time Iran went onto the offensive, Iraq had over 5,000 tanks, while Iran had about 500 left operational at any one time. Iran's divisions were entirely light infantry, while the Iraqis had substantial armoured and mechanized divisions with plentiful artillery and air support. A picture-perfect modern mechanized army.
On paper, the force Iraqis had should have been able to roll all the way to Tehran. Instead they got bogged down a few miles over the border, and then in '81 and '82 got routed by an infantry army half their size.
The human wave is a highly popularized but rather minor part of the Iranian tactical repertoir, and one they used more as a distraction to fix Iraqi attention rather than as the main effort. Had that been the sum of their tactics they could have charged at the Iraqis with millions of troops and made no headway.
More commonly, the Iranians would conduct extensive patrolling at night to find weakpoints in the Iraqi lines. Then they would move up as many tanks and artillery pieces as they could get to a critical sector and suppress the defenses, while the infantry charged through the gaps and into the Iraqi flanks and rear. The irreplaceable tanks would then withdraw, and the Iranian infantry would go about encircling and destroying the penetrated armoured and mechanized formations.
These tactics were highly effective against the Iraqis who despite their vastly superior potential mobility nevertheless tended to sit immobile in their firebases while the Iranians moved around them, to the point that time and time again Iranian RPG tank hunter teams were able to wipe out entire tank batallions and brigades as they sat static waiting for orders.
The Iranians were creative and intelligent in their attacks, and often used unorthodox tactics which stunned the rigid Iraqis, but they were hardly a juggernaught. Their leadership had been purged and many of their troops had little experience, and they had a chronic lack of firepower. The biggest thing the Iranians had going for them was the Iraqis were utterly execrable. Flanked Iraqi units would not respond, sitting still and just shooting from where they sat while Iranians swarmed over their positions, Iraqi units with clear opportunities for manuever and counterattack would not take them, and when ordered to attack the Iraqis would clank forward at halting speed in direct and poorly co-ordinated frontal attacks, allowing the footborne Iranians time to build up a defense.
The astonishing ease with which Iranian infantry could penetrate Iraqi lines is illustrated by the first Iranian attack on Basra. The Iranians attacked with 90,000 light infantry and 200 tanks. Facing them were over 200,000 mechanized infantry and over 2,000 tanks deployed in an impressive set of six defensive lines over 50km deep that the Iraqis had built over the summer of 1982. The Iranians hit the Iraqi lines on 19 June and by the 1st of July had penetrated to the very last defensive line before ferocious though clumsy Iraqi armoured counter attacks halted them and bogged the battle down into a stalemate that lasted into August, before the worn out Iranians finally decided to withdraw.
The battle was technically an Iraqi victory, but not much of one - an armoured and mechanized force, dug in prepared defenses had barely managed to halt a light infantry force half its size with negligeable armoured support. Worse, they had taken almost two months to do so, taking heavy losses in the process. Indeed Iraqi losses were so heavy that an entire tank division - the 9th - was disbanded.