The young couple flew into Wichita bearing, in the lovely swell of the wife's belly, a burden of grief. They came from a religious tradition where large families are celebrated and they wanted this baby, and it was very late in her pregnancy. But the doctors recommended abortion. They said that with her complications, there were only two men skilled enough to pull it off. One was George Tiller, a Wichita doctor who specialised in late abortions.

They arrived on Sunday, 31 May last year. As they drove to their hotel, a Holiday Inn just two blocks from the Reformation Lutheran Church, they saw television cameras. They wondered what was going on, a passing curiosity quickly forgotten. But when they got to their room, the phone was ringing. Her father was on the line. "There was some doctor who was shot who does abortions," he said. They turned on CNN. Dr Tiller had just been killed, shot in the head as he passed out church leaflets.

Now there is only one doctor left.

After the first two doors of bulletproof glass, a sign at Dr Warren Hern's Boulder Abortion Clinic warns that mobile phones and cameras will be confiscated. The receptionist hits the buzzer that opens the third bulletproof door. In the waiting room, a sad woman with a tight perm waits for her daughter. The receptionist lets you through a fourth bulletproof door and leads you down a green hall decorated with lovely pictures of nature, leaving you in a small room stocked with tissues and free condoms.

Twenty minutes later, the abortionist enters. Dr Hern is a tall man in green surgical scrubs, remarkably vigorous at 70, emphatic in speech and impatient in manner. He has a long face and no lips, which gives him a severe look. He apologises for having very little time. This is the day he sees patients for the first of three visits, giving them the seaweed Laminaria, which slowly dilates the cervix, and his normal caseload has been doubled by Dr Tiller's patients – including two with catastrophic foetal abnormalities and a 15-year-old who was raped, all in the second trimester, all traumatised by the assassin who calls himself pro-life, a phrase he cannot utter without air quotes and contempt. "They hate freedom," he says. He says it again. He warns me not to use anyone's name or it will put them at risk.

Walking out, he leaves the door open. You hear voices drifting down the hall. "The worst picture of an abortion doctor ever," someone says. "Is that Fox?" "Yes, Bill O'Reilly." "Supposedly they were there to protect us." You see a nurse you cannot name leading a middle-aged Indian woman to an examining room. "You'll need to undress from the waist down." You hear one of the receptionists you cannot name speaking in the carefully modulated voice the doctor prescribed in his first book, Abortion Practice, a classic in the field. Steps come down the hall. "I'm Dr Hern. Where are you from? Lie down now. Put your hand on your chest."

The phone rings. "Did you have an ultrasound? And they referred you here?"

Yesterday, the man arrested for Tiller's murder warned that more killings were on the way. All last week, the anti-abortion groups put out statements denouncing the murder and praising the result. One called the killer a hero. As a result, a squad of US marshals rushed out here last week on orders from the attorney general. One of them paces the hall. The second receptionist you cannot name asks him, "Did you see that guy out there smoking a cigarette?"

"Yeah, I saw him."

The first receptionist keeps talking. "If you can fax us the amnio. We don't know, we'll have to wait to see what your body tells us. Do you want us to run your Amex now?"

Another phone rings and the second receptionist answers. "It's basically a three-day process. We require that you stay here in Colorado."

The voices begin to overlap. "Are you on any medication?" "Have you had surgery in the last year?" "No, we don't have any genetics counsellors to interpret that for you." "We don't get a lot of protesters. It's a liberal and tolerant community." "If that changes, we will contact you." "No, you'll get up and get in your car and drive home. And, if you have a change of heart, please call us – our schedule is completely full and you'll be taking someone else's place." After another silence, a soft voice gets softer: "I also want you to know, we don't care what your reasons are. We're not going to judge you."

In the kitchen at the clinic, Dr Hern bolts down two microwave tamales. He talks fast and doesn't smile. "It is my view that we are dealing with a fascist movement. It's a terrorist, violent terrorist movement, and they have a fascist ideology…" Dr Hern goes on like that for some time. Long before the first doctor got shot back in 1993, he was warning that it would happen. He was getting hate mail and death threats way back in 1970, just for working in family planning. They started up again in 1973, two weeks after he helped start the first non-profit abortion clinic in Boulder. "I started sleeping with a rifle by my bed. I expected to get shot." In 1985, someone threw a brick through his window during a protest by the quote unquote Pro-Life Action League. He put up a sign that said THIS WINDOW WAS BROKEN BY THOSE WHO HATE FREEDOM. In 1988, somebody fired five bullets through his window. In 1995, the American Coalition of quote unquote Life Activists put out a hit list with his (and Tiller's) name on it. The feds gave them protection for about six months, then left them on their own.

"People don't get it," he says. "After eight murders, 17 attempted murders, 406 death threats, 179 assaults, and four kidnappings, people are still in denial. They say, 'Well, this was just some wingnut guy who just decided to go blow up somebody.' Wrong. This was a cold-blooded, brutal, political assassination that is the logical consequence of 35 years of hate speech and incitement to violence by people from the highest levels of American society, including but in no way limited to George Bush, Ronald Reagan, Jesse Helms, Bill O'Reilly, Jerry Falwell and Pat Robertson. Reagan may not have been a fascist, but he was a tool of the fascists. Bush was most certainly a tool of the fascists. They use this issue to get power. They seem civilised, but underneath you have this seething mass of rabid anger and hatred of freedom that is really frightening, and they support people like the guy who shot George – they're all pretending to be upset, issuing statements about how much they deplore violence, but it's just bullshit. This is exactly what they wanted to happen."

He goes on about TV host Bill O'Reilly for a while. Over the course of 29 shows, O'Reilly accused "Tiller the Baby Killer" of performing a late abortion for any reason at all, even so that a girl could attend a rock concert – a charge that is blatantly untrue. "O'Reilly is a disgrace to American society," he says.

But O'Reilly says he's just exercising his right to engage in vigorous debate, you point out.

"He's full of shit. This is not a debate, it's a civil war. And the other people are using bullets and bombs. I think O'Reilly is a fascist."

It's odd, you say, trying to be agreeable. They always go after the doctors, never the mums.

His eyes snap up. "What mums? The patients? They're not mums until they have a baby."

Late that night, Dr Hern calls you at your hotel. You are reading one of his many scientific publications. This one argues that man is a "malignant ecotumour" laying waste to the planet. A cancerous growth resists regulation. A cancer cell is a cell that reproduces without limits.

He's sorry, he says, but he must turn down your request to ride in his car to the Tiller memorial in Denver. He has to go with four US marshals in an armoured car. Even his wife can't ride with him. Same with dinner in a restaurant. "I will never be safe," Dr Hern says. "I'm always looking over my shoulder."

You use the term "partial-birth abortion" and he bristles. "It's a barbaric term for a procedure that was described at National Abortion Federation meetings in the early 90s by two doctors who didn't take the deadliness of the psychological warfare seriously." And then the Republicans took it up "and it became this obscene anti-abortion pornography". And when he tried to tell his colleagues, No, this is not the safest way to perform a delayed abortion, they accused him of working with the anti-abortion people and basically rode him out on a rail. "The whole thing turned into a tortured witch hunt – an incredibly painful experience."

Nothing pains him more than the disdain of other doctors. Sometimes the young ones ask to come in for an afternoon so they can learn to make a little money while their careers get started – they think it's as simple as changing a tyre. "There's no sense that this is an important operation that has to be done well, that a person's life depends on it." But let's face it, abortion is the lowest-status activity in medicine. That's why they always call their clinics Family Planning Centres or Women's Wellness Facilities, or some crap like that. Not his place: it's had the same name since 1975. "Because I felt that performing abortions was the most important thing I could do in medicine."

The patients can be upsetting, too. They're under terrible stress, of course, but sometimes they come in very angry. One had conjoined twins and would have died giving birth, but she exploded when told she couldn't smoke in the office. Some treat him with contempt: usually those who have been directly involved in anti-abortion activities. They hate all abortion except for their special case. One even said they should all be killed. Only 14, she came with her mother. "What brings you here?" Dr Hern asked. "I have to have an abortion." "Why?" "I'm not old enough to have a baby." "But you told the counsellor we should all be killed?" "Yes, you should all be killed." "Why?" "Because you do abortions." "Me too?" "Yes, you should be killed, too." "Do you want me killed before or after I do your abortion?" "Before."

He told her to leave. Her mother was very upset. But he isn't an abortion-dispensing machine. He's a physician. He's a person.

When Dr Hern takes his family home, he's escorted by the US marshals. When you come in, his mother is sitting in an easy chair surrounded by her family. She is 92, but she still has a girlish smile and twinkling eyes that summon gingham skirts and radio serials. You bend down to shake her grandson's hand. "So you want to be a pirate?" He nods and adds in a shy voice: "Or maybe a doctor."

The phone rings and Dr Hern goes to answer. He speaks in a heated voice. Hanging up, he's visibly agitated. "That guy got your number off the internet. He's a reporter.You have to change your number."

Dr Hern's mother explains that her number hasn't been listed for almost 40 years, because the anti-abortion people used to make nasty calls at two in the morning. Then there was a mix-up and it appeared in the phone book. Now she doesn't tell him about most of the calls. He's got enough to worry about.

As a boy? Always helpful. When he was just three, she'd give him a rag and let him dust. He sang in the choir. They got involved in church activities. But politically, they were always on the liberal side. He loved to go camping and fishing, and played the clarinet. His father was a carpenter, so they didn't have much money and couldn't afford to travel. But they always had exchange students from all over the world – Germany, Brazil, Italy, France, Pakistan, Japan, 13 countries in all. That was a way the kids could learn how other people lived. And he won second prize in Kodak's national contest for high school photography.

One thing that's probably important, she says, she had terrible migraines from as far back as she could remember. She'd get up in the morning and feel like her head was gonna roll down the hall. And one day she asked Warren what he wanted to be and he said, I really want to be a doctor, Mother. "He thought he'd be a neuro brain surgeon and maybe he could figure out what to do about my headaches."

That same year, he read a book about Albert Schweitzer healing the sick in Africa and announced, Mother, I'm going to go to Africa before I go to medical school. And he did, raising money so he could be a community ambassador with the Experiment in International Living. At college, he worked three jobs to pay his tuition. He learned ancient Greek and studied the Bible in the original. Then he sat her down and said, "I don't believe in this stuff any more." She said, "Well, you don't have to believe in it. Maybe I don't believe in all of it either."

In medical school, he saw his first botched abortions. Then he spent two years as a doctor for the Peace Corps in a Brazilian town so desperately poor, it wasn't unusual to see a dead baby on a rubbish heap. After that, he worked as a family-planning chief for the Nixon administration and spent some time in Appalachia, where he saw unintended pregnancies dragging families deeper and deeper into poverty.

But even after all that, there are still some family members who can't accept what he does. And other doctors, too. It really hurts him terribly, she says. "In his mind, he's trying to help women who desperately need help. And why can't these doctors, of all people…"

In his mother's opinion, he needs to retire.

The shooting? He called her as soon as it happened. He was trying to stay calm, but it was all he could do to keep from losing it. "I could hear the terror in his voice."

Has she ever tried to get him to stop? Especially now that he's kind of making himself a target. "I know that," she answers. "But that wouldn't do any good. He's got a mind of his own." The rims of her eyes are getting red. She moves her glasses and dabs at them.

Warren Hern's wife likes good coffee, so you meet at an espresso bar. She has a strong Roman nose and black hair that breaks against her cheeks in an ebony wave. In a charming mixture of English and Spanish, she tells you about growing up in Cuba, happy, sun-filled days and good medical training, until she started ducking the weekly "discussion" meetings and they told her she wasn't a good communist.

Later, working in a hospital, she saw women who tried to induce their own miscarriages bleed to death. Then she got pregnant. At 18 weeks, she went to her gynaecologist for the blood test. "They said, 'The baby's no good. You have a real problem.'" She went to a geneticist and a specialist in prenatal diagnosis. The geneticist suggested an abortion, "but the prenatal diagnoser, he said, 'What do you think about the baby?' And I said, 'I think he is good. I feel it in my soul, and I want to take him.' He said, 'Go and take your baby.'"

Labour lasted 36 hours, intensive care a month. The specialists told her the baby might have lifelong seizures or learning disabilities. To lighten her workload, she moved to Barcelona and took a job in an abortion clinic. She sees no contradiction in this. "I know that many women don't feel anything when they're pregnant and many women feel sad, feel angry. In this situation, you never can judge who's God. You need to respect women."

All that led to the man who would become her husband. She was at a medical conference in 2003 when Dr Hern came up to her and said, You are so beautiful. He was 64, she was 37. She was struck by his confidence. They began to send letters across the ocean and talk for hours on the phone. And he always showed her his fears and the loneliness of a life under siege by fanatics. She could relate: "When I was aborting in Spain, I finished the abortion of a young woman, first trimester. When I finished this procedure, she sat on the table, and said, 'Oh, doctor, you are really nice, you are such an angel, how do you kill babies?' I said, 'I'm sorry, I don't kill babies. I aspirate gestational sacs. You kill your baby.'"

But most important, Dr Hern always asked about her son. Other men did not do that. In the summer of 2006, they were married.But that was not their happy ending. At the end of May, when they were just back from a rafting trip in Utah, the phone rang. Warren took the call in his office, "and he didn't have any colour in his face. I said, 'What happened?' He said, 'A shooter shot George Tiller.' I thought it was crazy people, and he said, 'No Amor, these people killed him.'" Since that day, he has not relaxed one second.

Dr Hern barely has time to eat. Reporters come and go, the phone rings constantly, he disappears to the hidden rooms where no outsider is allowed to go. Every so often he snatches a minute or two to drop into the counselling room. You squeeze in a question. This idea about mankind being a "malignant eco-tumour". Doesn't it just invite the hate?

"I'm not inviting people to do anything. I'd like them to think. I do think that helping people control their fertility is highly consistent with helping people be responsible citizens of the planet. If somebody misunderstands it or tries to distort it, I don't give a shit. I'm sorry, I'm living in this country because I can say what I think."

But you're 70. You have ideas for a dozen books. Why not retire?

"I have important work to do here."

You want to cosy up to the next question, but there's no time, you blurt it out: What are your limits? When would you tell a woman no?

"There's no specific answer to that. I'm in the process of turning down somebody who's going to be 34, 35 weeks, with an important reason for doing abortion. I'm not going to do it." The phone rings. "OK. I'll be right there," and he's gone.

Hours pass. You've been moved to the nurses' office, where a soft felt sunflower weaves through the metal in-box. You are staring at a flyer advertising the clinic's services: "Specialising in late abortion for foetal disorders. Outpatient abortion over 26 menstrual weeks for selected patients with documented foetal anomaly, foetal demise, or medical indications."

The opponents of legal abortion often use the phrase "abortion on demand", implying there are no restrictions at all. This characterisation is untrue. It has always been illegal in the US to perform abortions after viability without a compelling medical reason. In Kansas, for example, where Dr Tiller practised medicine, the law for any abortion after 22 weeks requires two doctors to agree that failure to abort would put the mother at risk of "substantial and irreversible harm". But Dr Hern's long list of foetal abnormalities that have led women to his clinic ranges from anencephaly to dwarfism, and you know a few dwarfs. You like to think you'd be happy with a dwarf child.

He comes in, remembers that the US marshals don't like him to use this room because the window is too exposed, and walks right back out. You follow, asking about the patients who were supposed to see Dr Tiller.

"The patient I just finished was very unhappy to see me. I think they are very anti-abortion. She had a foetal abnormality, and she and her husband are just devastated. Stuff like that."

What kind of foetal abnormalities are we talking about? "One was Down's syndrome, another was a lethal brain abnormality along with a lethal heart abnormality. Another one had a catastrophic… we're not talking about cleft lip, we are talking about cleft face. There was no face."

He goes home, riding in the bulletproof car with three US marshals. You follow in a separate car. At home, there's a beautiful Bösendorfer piano with Beethoven on the stand and a primitive bow and arrow from the Amazon rainforest, where Dr Hern has cured diseases and conducted ethnographic studies for over 40 years. There are books everywhere, and many of the nature photographs he has published in environmental books and magazines. Then he leads you to his office. He sits down to bang out a letter to President Obama. "As you know, Dr Tiller was unarmed, vulnerable, and acting as an usher for his fellow worshippers."

It's four in the afternoon and he still hasn't eaten his miserable microwave tamales. Is he the abstemious type? "I enjoy food when I have a chance. I love to cook. Grown men lie down on the floor and cry with ecstasy over my paella."

What do the women do?

"They watch the men."

It's the first light thing you've heard him say. So you try to reach the emotional core everyone keeps telling you about. This woman you refused to treat, what was her reason?

"She was raped. I'm sympathetic, but I can't risk my medical licence for someone who just didn't get around to doing anything about it. I've done some cases over 36 weeks, but very few."

For what cause? "Catastrophic problems – anencephaly or lack of kidneys, you know. Lack of a brain."

The anti-abortionists say that in those cases, the woman should just give birth naturally and let God take the baby.

The sharp tone comes back. "Having a delivery is not a benign procedure. When you are trying to keep the baby alive, that increases the risk for the woman. And Reagan put in a bunch of rules about requiring to keep babies alive no matter how hopeless it is. You have people going to Europe to get away from that."

You mean the hospital requires them to save the baby?

"The hospital requires full resuscitation measures, no matter what."

Also, his seaweed procedure is very slow and gentle on the cervix. The tissue dehydrates, the collagen starts to pull apart, the uterus gets softer. If you do a forceful dilation, you're going to tear the cervix. All around, his way is safer.

Safer for the mum?

"Not for the mum," he snaps, "for the woman. Till she's had a baby, she's not a mum."

While you wait, you try to chat up his staff. Most don't want to talk on the record, but one says she's been working here for 13 years. Dr Hern is very caring with all of them, she says. He pays them well. He gives them insurance and a retirement savings plan, which is not routine in the abortion trade. Once, he took them all rafting down the Green River.

So what brings out his emotions?

"Well, I think it is difficult for him when women are experiencing pain and he's not able to control that for them."

Have you ever seen him cry?

"That's a question for Dr Hern."

Does it bother him when the patients show disgust? "That's a question for Dr Hern."

He is on the phone, talking with the editor of a scientific journal. "Well, I went to George's funeral in Wichita, and I was probably the most heavily protected son of a bitch in the state. I was surrounded by rings of marshals and they might've been able to get me with a shoulder-mounted rocket or something. But the grief of this situation was pretty hard."

The phone rings again. This time it's the president of the National Society of Genetic Counsellors, Steven Keiles. Dr Hern wants him to issue a statement denouncing the murder, the sooner the better. "I'm sorry, this is not very complicated. You make a statement and you issue it to the press, a one-page statement condemning the brutal assassination of a conscientious and dedicated doctor who helped tens of thousands of women." He slams down the receiver. "That guy is a fucking clerk. I have no patience for this kind of bullshit. George gave them so much money and so much help."

He starts ranting about the time the militant anti-abortion activist Randall Terry prayed for his death on national Christian radio. "These guys are just despicable. If anyone wants hope for the human species, don't talk to me."

A receptionist comes to close the door so the patients don't hear him. Later, he says, "You can never get used to this. I think we're hardwired, biologically, to protect small, vulnerable creatures, especially babies. The foetuses may not be babies, but some of them are pretty close." He suggests you read an essay called What About Us? Staff Reactions to D&E (Dilation and Evacuation). "The anti-abortion people quote the shit out of it. It's kind of anti-abortion porn for them. But the pro-choice people don't like it either. They don't like it when you talk about how it really feels to do this work." His voice is somewhere between bitter and proud.

So why did he write it? And what about this theory that man is a cancer? "I wrote it because, A, I'm a human being, and B, I'm a writer, and C and D, I'm a physician and I'm trying to understand what we're doing here."

You read the paper. He describes the reactions members of his staff have when they see residue of late abortions, which include "shock, dismay, amazement, disgust, fear and sadness". The later the pregnancy, the harder it is to accept. One assistant resented the patients for putting them through such a horrible experience. Two others described dreams where they vomited foetuses. Common coping mechanisms were denial, projection and rationalisation. The paper ends with the passage the anti-abortionists love to quote, always out of context; words so honest they are almost as painful to read as they must have been to write: "We have reached a point in this particular technology where there is no possibility of denying an act of destruction. It is before one's eyes. The sensations of dismemberment flow through the forceps like an electric current. It is the crucible of a raging controversy, the confrontation of a modern existential dilemma. The more we seem to solve the problem, the more intractable it becomes."

Dr Hern is in the basement doing an abortion. Today is Thursday, operating day. It's just after 8am, and very quiet. The waiting room is empty. So are the examining rooms. A receptionist tells you he just got done with a patient and should be back shortly.

A woman comes to the door. "Is it OK if I go outside for a minute?" "Sure. Knock on the door if you're starting to feel bad."

The phone keeps ringing. "If you have tissue samples," says the receptionist you cannot name, "That makes it logistically easier. Can I put you on hold one second?" She opens the door for the sad woman and her daughter. "Thank you," the daughter says in an emphatic tone that suggests she's not just talking about the door.

A few minutes pass and the phone rings again. "Good morning, Dr Hern's office. OK, did you get any measurements from the ultrasound? OK. And where was this done? OK."

When the calls slow down, the receptionist tells you about the time a pro-life reporter pretended to be looking for information and then quoted her by name. "They do these things to scare you."

The US marshals keep walking up and down the hall, carrying black bags that look ominously tactical. The receptionist opens the door again. It's a woman in an ankle-length Amish dress. "You've seen her before," she tells Dr Hern. "She was with another woman in the same kind of dress."

While you wait, you read another one of the doctor's essays. "It has been my practice to rupture membranes with ring forceps," it says.

At 11:30, the doctor comes up in a cheerful mood. "I have to go check the level of molecular degeneration in my tamales."

It's the second lighthearted thing you've heard him say. And when he comes back from the kitchen, he says another. "I identified a new species in my tamales. But I think with a gastroenterologist standing by…"

The receptionist smiles. "It's your risk."

The Amish women leave. He walks them to the door and says, "Give my regards to Dr H –"

In the nurses' office, the soft felt sunflower weaves through the metal in-box. A young woman wearing a 1920s flapper scarf comes up the stairs alone. At that very moment, you are reading page 83 of Abortion Practice, the section called Isolation: "One of the loneliest persons in the world is the woman who has not told anyone she is pregnant or considering an abortion. Some women have no one to whom they can turn; others insist on suffering alone as a form of self-punishment. The individual abortion counsellor may, and frequently does, fill that gap for both kinds of patients."

The woman in the flapper scarf stops at the receptionist's office. "Thank you so much," she says. "You're so helpful. You're wonderful ladies." Another woman stops at the desk. She's a Latina, here for her sister. "Can I wait? I want to say goodbye to everyone."

The phone rings. "Well, have you had an ultrasound? OK. If it's between 19 weeks and 24 weeks, it'll be between $5,000 and $7,500."

Five minutes later, it rings again. "No, we need to know what the measurements are before you travel. It's a measurement in millimetres and centimetres. Fax it to us. Everything is based on the measurement."

Now it's 1:47, and you're sitting down in the counselling room with the young couple who arrived in Wichita just in time to see the news cameras that surrounded the Reformation Lutheran Church. The woman has light brown hair and wears conservative glasses. She is calm, sombre and depleted.

As gently as you can, you ask her to tell you why she chose abortion.

"We had found out something was wrong at 28 weeks, seriously wrong. And they found out that it was going to put me, my health, perhaps in danger if I carried through to the end."

And it was a planned pregnancy?

"Oh yes. Absolutely."

And when you arrived in Wichita?

"We were caught between grieving about going through this and this awful situation."

You couldn't find a doctor closer to home?

"They do these kinds of procedures in Canada, where we come from, but because I was a very complicated case, and because I didn't feel comfortable with the way they wanted to do it, it was very high risk, I wanted to come to someone who is an expert."

Do you mind explaining why it was so complicated?

"The child had severe abnormalities."

You change the subject, asking what was wrong with the Canadian doctors.

"They do it very fast. They don't use the seaweed, they don't take their time, and it puts the woman at risk. And you're at risk of losing your uterus. I would like to have children, so I didn't want to have that risk."

And how did it go, the surgery?

"Well, Dr Tiller said that…"

Hern.

"Oh, sorry, sorry, sorry. Dr Hern said I was a very complicated case. He said it went well, but it wasn't an easy thing to do. It was painful physically and mentally."

You ask if there's anything else they want to say. The husband answers. "It's important that people have a choice. At the end of the day, when things go bad, you know? I mean, God forbid something happens to Dr Hern, where are we going to go next? Australia? China?"

Five minutes later, you catch Dr Hern in the nurses' office. Did their procedure take long?

"Yeah, it was 45 minutes. The average is five minutes. She was very far along. It was the position of the uterus, and she had a previous C-section, poor dilation, it was very difficult. I think any other procedure would have been very, very dangerous for her."

She was in danger of her life?

"Oh yeah. She would have risked having a ruptured uterus in an induction procedure."

In surgery, or in birth?

"Well, she's at risk, at this point, no matter what she decides to do. That's why I'm quite sure this was the safest option for her."

Later that evening, you will drive with Dr Hern's wife and son to the Temple Emanuel in Denver. He'll choke up when he ascends to the dais to say that George Tiller was "gentle, considerate and compassionate", then recover and roll into the refuge of his annealing anger: "This brutal, cold-blooded, premeditated political assassination is the inevitable and predictable result of over 35 years of rabid anti-abortion harassment, hate rhetoric, violence..."

When he comes off the stage to embrace the wife, he will break down in racking sobs. His son will stroke his shoulder. You will be standing right next to them, close enough to hear him say, "Amor, Amor, Amor," close enough to hear members of the audience – who came by word of mouth, because the rabbi considered it too dangerous to advertise publicly – whisper their gratitude. "Thank you for your courage." One woman squeezes his hand. "It's because of people like you that my relatives survived the 1940s."

Three weeks later, the woman from Canada calls you. She has some things she wants to tell you. It was the most tragic and terrible experience of my life, she begins. She has a son almost ready to start kindergarten, she was afraid she wouldn't survive to raise him, and she wants to have a big family, and the situation was so crazy with the marshals and the bulletproof glass and the constant fear of a mad killer with a gun. Dr Hern was under so much pressure. She could see the stress in his face. "Now I'm still recovering, and still sad and still mourning, and I realise how grateful I am that Dr Hern was able to take me under such quick and terrible circumstances. That's what gets me so upset. He's a doctor who is trying to help people. It's shocking that people want to hurt him."

Without Dr Hern, she says, she doesn't know what she would have done. It's crazy he's the only one left. She is grateful, so grateful that she will be here to raise her son. And as the words tumble you hear, in the urgency unleashed by her deliverance, a love too sad for sermons, too personal for headlines, a private benediction, the abortionist's reward, the love song of Warren Martin Hern, MD.★

• Copyright John H Richardson. A longer version of this article originally appeared in US Esquire.