George Tiller was one of the most infamous physicians in the pro-life world. The Kansas abortion provider regularly aborted fetuses, both disabled and healthy, in their final trimester, which few others are willing to do. He further stoked religious ire by retaining a chaplain who offered cremated ashes to parents and baptized aborted remains. But his practices do not fully explain his murder at Wichita’s Reformation Lutheran Church on Sunday.

Violence in the pro-life movement has emerged relatively late in the abortion conflict, only recently claiming the lives of abortion providers. To really understand Tiller’s death, therefore, we need to look beyond his own biography to some of the peculiar historical developments that have made abortion politics in America so distinctive and tragic. Why, when tensions over abortion seem to be at an all-time low, have we seen a spike in anti-abortion violence?

When conflict over abortion gained steam in the 1960s, it was not marked by much stridency despite the political convulsions of that decade. Instead, both sides worked through normal electoral channels, especially by lobbying state legislatures. Pro-choice reformers quietly won incremental victories in states such as California, New York, and Colorado. Pro-life forces, meanwhile, counter-mobilized by lobbying state legislatures and won some notable victories in states like Michigan. Notably, however, there were no street protests, much less clinic bombings or physician murders. As James Risen and Judy L. Thomas depict in Wrath of Angels: The American Abortion War, prior to Roe v. Wade, the pro-life movement was dominated by Catholic doctors and suburban housewives who lobbied their state representatives.

In 1973, Roe v. Wade dramatically changed abortion politics and the right-to-life movement in particular by pushing much of it out of the state houses and into the streets. Activists began staging “sit ins” as early as 1975 in Washington D.C. The pioneers of the “rescue” movement, as it came to be called by its evangelical heirs, reasoned--correctly, as it turned out--that they had little chance of passing a Human Life Amendment to the Constitution or changing the makeup of the court. “It was frustration and despair that split the anti-abortion movement in two,” Risen and Thomas explain. “Those who refused to accept the mainstream, incremental lobbying efforts moved into a ‘direct-action’ movement.”

Viewed in this context, the radicalization of the pro-life movement was in many ways a rational adaptation to the shifting political landscape. Roe guaranteed that electoral politics would bring only marginal victories for the pro-life movement, such as parental consent laws and a ban on partial-birth abortion. As Risen and Thomas conclude, “Roe led almost inevitably to revolution and sent opponents out into the street.” The court decision birthed one of the largest campaigns of civil disobedience since the anti-war movement, even as other ’60s movements were dying. According to the National Abortion Federation, there were more than 33,000 arrests and 600 blockades between 1977 and 1993.

Though a tradition of Christian pacifism held sway over the first generation of activists in the rescue movement, some grew exasperated by the late 1970s by the small, ineffectual clinic blockades in cities such as Washington D.C. and St. Louis. Activists such as Joan Andrews began attracting headlines for vandalizing abortion clinics. Once caught, her dogged refusal to cooperate with the criminal justice system earned her solitary confinement and fame as a pro-life martyr. Midnight bombings began. Radicals orchestrated 28 bombings between 1977 and 1993. Some of the perpetrators were Catholic leftists who had cut their political teeth on the anti-war movement. In their destruction of abortion clinics and equipment, for example, such radicals were trying to consciously imitate the “Plowshares” anti-nuclear movement.

Yet as combustible as these circumstances were, abortion providers were not in real jeopardy until recently. Other than the kidnapping of abortion doctor Hector Zevallos by the Army of God in 1982, the radical fringe of the rescue movement largely limited its violence itself to property damage throughout the 1970s and ’80s. Bombings were timed successfully to avoid human casualties.

By the late 1980s, the movement had grown bigger and more aggressive from an influx of evangelical fundamentalists. Unlike the small sit-ins orchestrated by leftist Catholics, Operation Rescue orchestrated large clinic blockages in cities from New York to Los Angeles. The promise of this campaign--and the influence of Operation Rescue--actually controlled violence-prone extremists. Throughout the 1980s, for instance, there was an inverse correlation between abortion-related violence and the success of civil disobedience. As Christopher Keleher found in the DePaul Law Review, “the drop in the number of violent incidents correlated with increase in the number of nonviolent protests.” The nonviolent, civil disobedience seemed to control violence-prone radicals by providing them with an outlet for their pro-life zeal.

But this institutional restraint largely disappeared when Operation Rescue imploded in 1992, partly because of the autocratic management style of its leader, Randall Terry. And perhaps more importantly, many activists simply exhausted their energy and vacation time in jail. These internal failures were greatly compounded by the passage of the Freedom of Access to Clinic Entrances Act under the Clinton administration, which made it a federal crime to participate in clinic blockades. The collapse of Operation Rescue released violent radicals from any institutional constraints, leaving them to their own darkest desires. As Risen and Thomas explain, “Within two years of [the collapse of rescue], what was left of the movement was dominated by extremists who refused to place any limits on direct action to stop abortion.” Fueling radicalism even further, the Supreme Court upheld Roe just months after the collapse of Operation Rescue.

Violence soon followed. In March of 1993, the first abortion provider, David Gunn, was shot to death. The next year, four more lives were taken on the heels of the publication of A Time to Kill, a murderous manifesto authored by Michael Bray. In 1998, two others died at the hands of pro-life extremists. It was this radical wave of violence, which most observers believed had already crested, that took George Tiller’s life.

After seven deaths in the 1990s, the editors of the Harvard Law Review argued that the crackdown on clinic blockades by the federal government closed one of the only remaining “safety valve[s]” for democratic dissent. The consequence, according to its editors, is that as we have “foreclosed nonviolent outlets of dissent, violence has increased.” First Roe pushed activists out of electoral politics and into the streets, and then the federal crackdown on civil disobedience pushed many others off the streets as well--into even darker corners. So while pro-life activism is declining on a broader level, the lives of abortion providers have never been more imperiled by extremists in the right-to-life movement.

It is, of course, impossible to rerun history without the intervention of the Supreme Court and a federal crackdown on civil disobedience. We don’t really know if the passions this issue excites could have been channeled in a more constructive and peaceful direction, and it is likely that violence would have increased without the government’s involvement. Nonetheless, it is ironic that turbulent 1960s was the decade in which the coolest heads prevailed in abortion politics--and that the lack of radical institutions today may be what has bred the latest round of violence.

Jon A. Shields is assistant professor of government at Claremont McKenna College and author of The Democratic Virtues of the Christian Right (Princeton University Press, 2009).

By Jon A. Shields