If the attacks on the Pentagon and the WTC on 11 Sept 01 are _crimes_, not acts of war, then they are _terrorism_ according to international law.
If the attacks on the Pentagon and the WTC on 11 Sept 01 are _acts of war_, then they are _not_ terrorism according to international law, since law doesn't classify acts of war as terrorist (if it did, many states, including the USA, would get into legal and/or public relations trouble): the attack on the Pentagon is an attack on a legitimate military target with "collateral damage," (as the US government puts it when its military action causes civilian casualty), which is arguably a war crime; and the attack on the WTC is clearly a war crime.
In short, calling X terrorism means that you are not treating X as war & the perpetrator of X as combatant in the legal sense, _as treating X as war decriminalizes it (unless X is also a war crime)_. Legally speaking, it's better to be treated as combatants in war rather than criminals which terrorists are, as combatants have more rights than criminals. That is, for instance, why the Zapatistas, who have taken very few armed actions & probably wish to take no more of them, have nonetheless argued that they are combatants at war, who then must be accorded rights of combatants according to international law, rather than treated as criminals. -- Yoshie
* Calendar of Anti-War Events in Columbus: <http://www.osu.edu/students/sif/calendar.html> * Anti-War Activist Resources: <http://www.osu.edu/students/sif/activist.html> * Anti-War Organizing in Columbus Covered by the Media: <http://www.osu.edu/students/sif/media.html>