If other things were equal, technological differences might be decisive, but they are not. Once again, the subjective has to be factored in. To take one example, the US government has nuclear weapons and brandishes them constantly, but can it actually drop them? That depends on whether the publics in the USA and the rest of the world morally accept its doing so.
The reason why the US government has been able to win many wars speedily since Vietnam is that it has only chosen the sort of targets that it can easily destroy and the kind of limited objectives that it can achieve: Panama, Grenada, and Haiti. The "regime change" in Yugoslavia was not accomplished by the Kosovo war; it happened only when a large number of Serbs themselves, with the help of US funding, rose up to overthrow the Milosevic government, and Milosevic chose not to hang onto power by firing on Serbian protesters. Somalia was a military and public relations debacle.
The US military has yet to directly and massively engage determined guerrillas with a clear goal and faith in their cause, like FARC, or conventional armed forces with a high level of morale who are loyal to popular leftist heads of state, like Castro and Chavez, mostly because there have not been many of them on the left, but also because doing so requires winning the "hearts and minds" of the populations, that is, winning them away from the guerrillas or popular leftist heads of state supported by loyal armed forces. Winning war of this kind requires hegemony and consent, rather than simple domination. -- Yoshie
* Calendar of Events in Columbus: <http://www.osu.edu/students/sif/calendar.html> * Anti-War Activist Resources: <http://www.osu.edu/students/sif/activist.html> * Student International Forum: <http://www.osu.edu/students/sif/> * Committee for Justice in Palestine: <http://www.osu.edu/students/CJP/>