Let's face it: who likes dictatorships? To overthrone a regime there is a price to be paid and nobody will pay that price unless there is something to gain(i.e economically or geo-political). I'm ok with that as long as it's done right(which was not case with Iraq) but let's not pretend that it's moral to let these pesky dictators die by natural causes.
In a country's case "the cancer" always has to be replaced with something. The US definitely has no working recipe for that, as several decades have shown.