"...is a policy or ideology of violence intended to intimidate or cause terror..."

Wikipedia cot'd:

"...for the purpose of "exerting pressure on decision making by state bodies."[1] The term "terror" is largely used to indicate clandestine, low-intensity violence that targets civilians and generates public fear. Thus "terror" is distinct from asymmetric warfare, and violates the concept of a common law of war in which civilian life is regarded. The term "-ism" is used to indicate an ideology —typically one that claims its attacks are in the domain of a "just war" concept, though most condemn such as crimes against humanity.

Terrorism is more commonly understood as an act which is intended to create fear (terror), is perpetrated for an ideological goal (as opposed to a materialistic goal or a lone attack), and deliberately targets (or disregards the safety of) non-combatants. Some definitions also include acts of unlawful violence or unconventional warfare..."

Ezra Klein in today's Wapo:

"As The American Prospect's Ann Friedman writes, this has to be understood in context. It is the final, decisive act in "an ongoing campaign of intimidation and harassment against someone who was providing completely legal health-care services." That campaign stretched over decades of protests, lawsuits, violence, and, finally, murder. The different elements were not always orchestrated. But the intent remained constant: To counter the absence of a statute that would make Tiller's work illegal with enough intimidation to render it impossible.

This was, in other words, a political act. Tiller was murdered so that those in his line of work would be intimidated. In conversations with folks yesterday, I heard well-meaning variants on the idea that it would be unseemly to push legislation in the emotional aftermath of Tiller's execution. I disagree. Roeder was acting in direct competition with the United States Congress. And it's quite likely that he changed the status quo. Legislative language and judicial rulings had made abortive procedures legal and thus accessible. Yesterday's killing was meant to render abortive procedures unsafe for doctors to conduct and thus inaccessible.

If a woman cannot get an abortion because no nearby providers are willing to assume the risk of performing it, the actual outcome is precisely the same as if the procedure were illegal."

In completely unrelated news, three weeks ago Afghan "Pro-Daughter" Activists released poison gas near a local girls' school to protect their precious minds from the corruption of education.