The American definition of terrorism excludes acts openly done by recognized states. The definition has five components, all of which must be present for an act to constitute “terrorism”. To qualify, an act or attempted must be:

1) Premeditated,

2) politically motivated,

3) violence,

4) against non-combatants, and

5) by sub-national or clandestine agents.

This is an excellent article, but I think criteria #5 should not be there. It's like admitting that your own acts would constitute terrorism if it weren't for an arbitrary exclusion in the definition.