Was this week's murder of a British soldier a "terrorist" attack?

The argument in this Guardian column argues that terrorism is defined as attacks directed at civilians:

That this was a barbaric and horrendous act goes without saying, but given the legal, military, cultural and political significance of the term "terrorism", it is vital to ask: is that term really applicable to this act of violence? To begin with, in order for an act of violence to be "terrorism", many argue that it must deliberately target civilians. That's the most common means used by those who try to distinguish the violence engaged in by western nations from that used by the "terrorists": sure, we kill civilians sometimes, but we don't deliberately target them the way the "terrorists" do.

But here, just as was true for Nidal Hasan's attack on a Fort Hood military base, the victim of the violence was a soldier of a nation at war, not a civilian. He was stationed at an army barracks quite close to the attack. The killer made clear that he knew he had attacked a soldier when he said afterward: "this British soldier is an eye for an eye, a tooth for a tooth."

The US, the UK and its allies have repeatedly killed Muslim civilians over the past decade (and before that), but defenders of those governments insist that this cannot be "terrorism" because it is combatants, not civilians, who are the targets. Can it really be the case that when western nations continuously kill Muslim civilians, that's not "terrorism", but when Muslims kill western soldiers, that is terrorism? Amazingly, the US has even imprisoned people at Guantanamo and elsewhere on accusations of "terrorism" who are accused of nothing more than engaging in violence against US soldiers who invaded their country. 

More at the link (those who reflexly dislike Glenn Greenwald's column can give it a pass).