Unless you mean the Muslims, it is not at all clear to me that this is the case. The West has been too brainwashed into "limited war" that spares "civilians". Look at our last really unequivocal victory - WWII. Our enemies' cities were in ruins, their people killed in large numbers, those still alive prostrate before us, their evil ideologies erased. We ran those countries with a velvet-gloved iron fist until they were ready to join the civilized Western world.
Do we have the will to do it again?