Soccer question usa and the world cup?

what would it take for the untied states to win the world cup and to be competitve. Are americans soccer players just not good enough to compete with the best of the world, is it their training prepartions or is it because their pion is just not as strong as other power house countries. What do you think. If Mia Hamm was playing could she enhance the American Chances and win the world cup in the men's league?