To be fair, the U.S. military is very effective against the individual people they are fighting at any given moment. Kill ratios in recent conflicts are of the order of 100:1. It's just that for every insurgent you kill, you create 10 more. Unless your goal is to just depopulate the rest of the globe (something I wonder about, given recent U.S. foreign policy), you can't actually win this war without addressing the conditions that lead people to hate the U.S. in the first place.