Umm... I’m not sure where you have been for the past few decades but the United States IS a powerhouse for changing the world. In fact Americans have been such a powerhouse that they haven’t taken the time to think of themselves. America contributes to numerous peacekeeping organizations and the general global effort towards various goals... but the thing is that America is so nosy about other affairs (Iraq, Vietnam) that they never take the time to repair their own societal infrastructure. It’s really easy to say “Well I want to change the state of immigration! It is bad! Let’s fix it and make America a better place?” What the hell are you gonna do about it?