I could be wrong, but I look at the debate this way; If the 9mm or 40 cal goes through the target, then how much of their energy gets dumped into the target? Both tend to go through their targets, but the 45 tends to remain. Therefore, the .45 ACP and LC dump 100% of their energy into their target. The .45 is aprox 11.45mm compaired to the 9mm's... well... 9mm.
Bigger holes make more blood flow! In Somolia, the 9mm drilled holes through the Skinnies. The .45 broke bones and planted them.
Just a thought... Did yall know the military is going back to the .45? The Special Forces and the Marines are back to the 1911 or another pistol for the .45.