What do you mean? The war in Iraq has outlasted 3 US presidents, so clearly "different leadership" just doesn't work in practice.
IMO the US should completely change the modus operandi. "Invade & install new regime & call it democratic & steal oil" just isn't a good proposition for the local population. Unless the US can improve the proposition (to match China's "we give you lots of money and improve your quality of life") foreign military interventions just won't work.