The murderous rampage at a Colorado Springs, Colorado, Planned Parenthood clinic had barely ended before the left began using it to try to shut down the abortion debate.

The shooting was an act of terrorism directed against women’s “health-care services,” and incited by the inflammatory rhetoric around video exposés of Planned Parenthood. The triple murder had been nearly inevitable given, in the words of Planned Parenthood President Cecile Richards, the “toxic” environment created by “hateful rhetoric.”

Never mind that the shooter, Robert Dear, apparently had no connection to the Republican Party or the pro-life movement, or to much of anyone, if initial reports are to be believed. He was a loner who avoided eye contact and dispensed paranoid advice to neighbors on how to avoid detection by the government.

It is possible that Dear decided to shoot up a clinic to make a point, in which case his crime was an act of terrorism. It also is possible that, clearly disturbed, he committed a random act of violence. Or it might be something in between. According to initial reports, he told police after he surrendered “no more baby parts,” but also rambled incoherently. The police haven’t yet determined a motive.

Regardless, the rush to apportion blame as widely and carelessly as possible is on. As James Taranto of The Wall Street Journal points out, when Islamic terrorists strike, we get immediate assurances of the peaceableness of Islam. When an oddball drifter attacks a Planned Parenthood clinic, we hear about the collective guilt of pro-lifers.

Their alleged offense is to take exception to Planned Parenthood as the nation’s foremost provider of abortions, and to recoil in horror at its gruesome practices exposed in Center for Medical Progress videos. No matter what rules the left hopes to impose on the debate, dismembering unborn children and selling off their body parts is inherently controversial. So is abortion.

Planned Parenthood likes to describe itself in the most anodyne terms as providing “health-care services” to women. But no one would care about the work of Planned Parenthood if all it did was provide routine exams and birth control.

In the wake of Colorado Springs, it hopes to delegitimize its critics. But a broad-based movement shouldn’t be tarred by the crimes of one individual (or the excesses of a tiny fringe). In the prelude to the Civil War, there wasn’t any doubt about the motives of John Brown, a domestic terrorist committed to fighting slavery. His raid at Harpers Ferry didn’t silence abolitionists, although Southern partisans used it to galvanize opinion against them. (One Southern newspaper thundered afterward, “We regard every man in our midst an enemy to the institutions of the South who does not boldly declare that he believes African slavery to be a social, moral, and political blessing.”)

When the Weathermen were setting off bombs in the early 1970s, no one said to stop criticizing the Vietnam War. When the Black Panthers were shooting it out with cops, no one said to stop advocating for black rights. When Puerto Rican separatists waged a campaign of terror, no one said that vigorous advocacy of Puerto Rican independence should be off-limits.

Today, most acts of domestic terrorism are committed by radical environmentalists, albeit they typically only involve property damage. Does this mean that we need to tone down the rhetoric about climate change and the allegedly catastrophic threat it represents to the future of humanity? If so, someone needs to get word to John Kerry and Barack Obama in Paris immediately.

The pro-life movement is overwhelmingly peaceful and prayerful, and seeks a more just society where all are welcomed into life. Robert Dear, who wantonly took three lives and wounded nine others, is the antithesis of all that it stands for. Neither his atrocity nor the smears of the left should hinder its work. The debate over abortion will — and must — go on.

Rich Lowry can be reached via e-mail: comments.lowry@nationalreview.com.