I don't subscribe to the idea that criminal organizations engage in political terrorism. There motivation is usually monetary gain, not forming or reforming a political entity.
This has probably always been a false assumption, but it is certainly a false assumption today. Political power is political power regardless of the reason one seeks it. It is a false dichotomy to claim terrorists are political and criminals are profit motivated. That line only exists in our academic world, it is a line drawn to support bureaucratic rice bowls (who owns the problem and who gets the funding to deal with it). If terrorism is directed against the citizens and/or the government it is political. Political motivation can be quite varied, thus the character of the terrorism can vary significantly, but at the end of the day they often both have political aims. We have an outdated lexicon from the Cold War that no longer accurately describes the world we live in today (if it ever did).

Mike,

would such terrorist tactics have worked had Palestine not been ruled by a liberal democracy; and moreover, one which was broke and beholden to a US not reluctant to exert pro-Jewish pressure--a US in which the Truman Administration and congressional Democrats were slipping into an increasingly pro-Zionist stance. Notably, substantial numbers of Palestine Police transferred to Malaya, where they were less constrained (and more successful) in countering terrorism...
I'm not as familiar with this history as I should be. Are you arguing that liberal democracies are more vulnerable to terrorism than other forms of government? Regarding your point about Malaya, it seems you're arguing that countries willing to implement rather severe population control measures are more successful than countries that won't. That seems logical, but the West defeated a wide range of left leaning terrorist groups in Europe and the U.S. without implementing severe population control measures, so it seems there are more variables involved than this.