Limited or unlimited war. Wars are won when they are actually winnable.
"Kick Saddam out of Kuwait" is a concrete achievable metric. Cut off supply lines, destroy units in Kuwait, and you're done.
"Make people act in a manner entirely contrary to their culture and against their primary incentives" is not an achievable metric.
Vietnam was lost because the puppet Southern government was corrupt and inefficient. The communists offered xenophobia, promised material gains, etc. Especially the communists played to the peasants' incentives and culture. Our side allegedly offered inequality and vague concepts like "freedom". Better in the long run, but not from the perception of your average villager.
The key to winning wars is to fight wars that are winnable. This sounds simplistic bordering on retarded, but is the bedrock of warfare. Changing a hill with a sharp stick against infantry in foxholes with automatic weapons is suicide. Charging a hill with tanks supported mechanized infantry and full CAS against infantry in foxholes with automatic weapons is pretty certain victory.
Restrictive idiotic ROEs are not the problem. It's getting in a fight you can't win. Trying to change Iraq or Afghanistan into a sandy version of Seattle is an unwinnable fight. If your success relies entirely on the civilian population acting in a way that is entirely foreign and contrary to their nature, you won't win unless you pull a Soviet Union or Taliban. Torture, genocide, no system of law, etc.