Terrorism is not an ideology. What makes something a terrorist act is not the political cause that motivates it or the background of the people involved. Terrorism is a particular type of violence, in which random or symbolic targets are attacked to intimidate them. The aim is not to achieve strategic or military goals directly, but to publicize a cause and put pressure on others to change their policies. Because it targets people who are at most peripherally involved in the conflict and may bear little responsibility for it, terrorism is almost universally condemned. Even those who strongly oppose our policies generally agree that blowing up civilians is the wrong way to attack us.
When Joe Stack flew his single-engine Piper Cherokee into an IRS building in Austin, it was an act of terrorism. It's not the superficial resemblance to the September 11 attacks that makes what Stack did terrorism. It's the fact that he makes clear in his angry suicide note that the attack was not aimed at the particular building he attacked but rather at our political system in general, and that he hoped that the attack would make people "wake up and begin to see the pompous political thugs and their mindless minions for what they are." Violence, he believed, was the only thing that could wake us up. "Nothing changes without a body count," he wrote.
But reporters and government officials have been reluctant to call what Stack did terrorism. On Fox, Catherine Herridge made a distinction between Stack's act and "Terrorism with a capital T." It's certainly fair to point out that Stack was not acting as part of a larger terrorist conspiracy. And one can make the case that in spite of his note that what Stack did was as much a burst of murderous insanity as a deliberate act of terrorism. Nevertheless, it was still explicitly an act of terrorism. Only its scale separates it from the Oklahoma City bombing.
If we're reluctant to call Stack's attack what it was, it's because "terrorism" has become a code word for what Muslim jihadists do. We don't apply the same standards to white Americans like Stack, whose frustration many Americans can more easily relate to. In the same way, many pro-life activists were unwilling to condemn Scott Roeder's assassination of Dr. George Tiller as an act of terrorism, even though Roeder targeted Tiller as part of his opposition to abortions. This double standard matters because, as Glenn Greenwald says, fear of terrorism has become a defining feature of political debate. Too often the claim that our enemies are terrorists is used to justify denying them even the most basic of human rights. The truth is that not all who oppose us are terrorists—whereas sometimes people who resemble us actually are.