They've sustained their insurgency only because of the ample money and arms that were scattered around Iraq. Without these tools, notwithstanding the superior training and experience of the Baathist insurgents, the Sunni Arabs would have failed pretty quickly in their effort to regain power.
What has been most evident and astounding has been that despite the almost complete lack of experience in governing or military matters found in the majority Shias, that the government has built up its strength pretty steadily these last four years despite the terror and insurgency.
And one indicator that we were winning all along is this interesting little metric that I noticed three years ago:
The rule of thumb for the last century or so has been that for a guerrilla force to remain viable, it must inflict seven casualties on the forces of the government it is fighting for each casualty it sustains, says former Canadian army officer John Thompson, managing director of the Mackenzie Institute, a think tank that studies global conflicts.
I assume this reflects the superior ability of a government to generate combat power over their insurgent enemies. To overcome that edge, an insurgency must kill at a ratio that allows them to shift the balance of power and so go up the escalation ladder from terror, to insurgency, to pitched battle and defended territory, and finally to marching on the capital and winning the war.
Instead, the enemies in Iraq have gone down the escalation ladder. Instead of direct attacks, the enemy relies on IEDs and indirect fire attacks. Direct attacks are rare. The casualty ratio is why this is so. Overall (and this is just by eyeballing KIA data I've seen without doing the tough math), it appears that we've suffered the loss of 80 US troops, 8 coalition troops, and 200 Iraqi army and police each month. That's about 290 per month, on average.
The enemy has lost about 380 per month over the war. And I'm assuming this is just the Sunni insurgents and terrorists rather than being inclusive of Shia militias.
So rather than killing government forces at a 7:1 ratio, the enemy has killed Iraq and Coalition security forces on a 3:4 ratio. Kill ratios are not the measure of winning, it is true, but with a kill ratio this favorable to our side, our shield behind which the Iraqi government could build up its governing and security institutions was quite solid. Had the enemy killed at a 7:1 ratio, we would have had far greater difficulty creating an Iraqi government form Shias who had almost no experience in governing or leading troops in battle.
When we look back on this war, assuming we don't hand the enemy a wholly unearned victory by just retreating, we'll wonder why anybody ever assumed that an enemy victory was inevitable rather than our victory being the sure thing.