Editor's note: Dr. George Tiller managed to survive the bombing of his Wichita clinic. He survived being shot in both arms. He was arguably the most high-profile target of anti-abortion violence because he was one of the few doctors in the country who performed late-term abortions, which by law are limited to circumstances where a fetus would not be viable or a woman would face "substantial and irreversible impairment of a major bodily function" without the procedure. He was finally gunned down Sunday inside the church he attended.

Many blame his death not only on Scott Roeder, the man who allegedly pulled the trigger, but on the hateful rhetoric and aggressive tactics of groups like Operation Rescue, which coined the phrase "Tiller the Killer." Roeder is known to have posted messages on Operation Rescue's site, including one in 2007 that called Tilller "the concentration camp Mengele of our day [who] needs to be stopped ...."

While the group's president has publicly denounced the murder, critics say Operation Rescue encourages and instructs people like Roeder by publishing home addresses of medical staff while talking up biblical justice. In response to the killing, Operation Rescue founder Randall Terry called Tiller "a mass-murderer," implying that his killing was justified. "He sowed death. And then he reaped death in a horrifying way," Terry said Monday.

Here, Angela Williams of Chapel Hill recalls an experience 20 years ago in which she faced down abortion opponents organized by Operation Rescue and became convinced of their violent extremism.

In 1989, Operation Rescue came to Washington, D.C., where I lived while attending graduate school. They planned a rally at a football stadium and advertised it as a big national event. People from all over the country would descend on D.C. to basically take over clinics in the area and shut them down.

A group of us in the direct action group OUT! (Oppression Under Target!) worked with a liberal Catholic peace and justice organization called the Quixote Center and other groups to organize a counterprotest. I had done protests surrounding AIDS and gay rights, but this was the first clinic defense I ever did. It was very different.

At the time, I had this fairly naive notion that abortion protesters didn't believe the way I did, and of course we both have the right to say what our beliefs are. I didn't yet think of them as violent. So I was really surprised by what happened.

We knew what Operation Rescue planned to do: They would create a circle of people around the building, starting at the entrance. As the police arrest the person blocking the door, the next person steps in. With enough people, they can keep the doors blocked and the clinic closed all day.

Our goal was to create a line of people that broke their line, so that eventually clients could enter the clinic again. But Operation Rescue kept secret the locations of the clinics they planned to target.

We had a map of different clinics in Washington, and we positioned groups of people in cars around the city near the clinics. Several people from OUT! infiltrated the event at the stadium. This was before cell phones, so they used walkie-talkies and pay phones to get the word out as soon as Operation Rescue announced which clinics they were going to.

We didn't count on them going to Baltimore. My group was the closest to Baltimore, and we got there first. But Operation Rescue beat us there.

It was chaos.

There were a lot of very angry people screaming and holding fetus signs, yelling at everyone that they're murderers. By the time we got there, their line was three-people-deep around the building. They sang, they yelled. They were blocking the front door. The police were there in force. The newspeople showed up.

We had two or three carloads of people, while they had busloads. Reinforcements on our side eventually arrived, but we were seriously outnumbered. More groups were showing up every hour or so.

I stood right in front of a woman who was screaming in my face, yelling "murderer," just saying all these horrible things. I was thinking, "It's going to be really hard to stand here all day and take this." So I tried to think of a nonviolent way to just get this woman out of my face. She kept putting this photo of a dead baby right in front of me. So I licked her arm. She was completely appalled, but it worked. She didn't get in my face again.

Our line was trying to intersect their line so they could not continue their circle around the clinic. After a couple of hours, they knelt to pray, and I had my chance. Since I was the first person in my line, I could step over them. So I used the horse stance, a very solid karate stance, to step completely over their line, which at that point was two people deep.

Immediately, two people punched me right in the backs of my knees. Then someone else was on my back. They were trying to knock me down. My face and arms scraped against the brick wall as I slid down.

I was able to remain standing, but I got pretty beat up from it. My face and arms were bleeding. The Operation Rescue protesters kept screaming at me, angry that I had broken their line.

I stayed put for another few hours. Because our line cut off their people from getting to the door, clinic volunteers managed to escort some people into the building by surrounding them. The people from Operation Rescue were screaming, "Don't murder your baby!" and holding up pictures of aborted fetuses. But they may have just been people going inside for a medical appointment.

As I wiped the blood off my face with an old T-shirt, I felt angry and shocked. Up to that point, I had this idealistic belief that although we took opposing positions, we were just there stating our beliefs. I grew up in South Carolina, and I guess I had this notion that anti-abortion protesters would be like the Sunday school teachers who believed in life and were also, say, opposed to the death penalty.

Since then, I've learned a lot more about Operation Rescue. Part of their standard operating procedure is to intimidate people with threats of violence. I think they train specifically for what to do if someone breaks their line; when I did, the response was immediate.

This group in some ways is not unlike the Taliban: an organization of religious zealots who really are not respectful of other points of view, who want to force their beliefs on everyone else and are willing to resort to violence in order to do that. They were giving out Dr. Tiller's phone number and calling him a child-killer. That's terrorism.

The fact that the Supreme Court could go either way on abortion rights means these extremists are willing to heighten their actions. There's a level of desperation and religious anger now that's really frightening.

It's a reminder to all of us that there are people who will try to take away other people's rights if it fits their agenda, and how important it is to preserve the right to choose.