A shooting in a Colorado Planned Parenthood clinic appears to be the latest in a lengthy history of incidents targeting U.S. abortion providers. Three people died, including a police officer, and nine were injured after authorities say a 57-year-old man opened fire in a clinic in Colorado Springs before surrendering to officers.

The clinics have long been a target of crime, motivated by attitudes against abortion, according to the National Abortion Federation. Between 1977 and 2014, abortion providers in the U.S. and Canada have experienced thousands of incidents, some of which have been violent. The group tallies eight killings of abortion providers, while death threats, anthrax threats and arson measure in the hundreds.



Lindsey Cook for USN&WR; Data: National Abortion Federation

Even without the threat of violence, clinics are targets of harassment, blockades and hate mail. The actual totals are likely much higher, as these are only the ones which have been reported.

Lindsey Cook for USN&WR; Data: National Abortion Federation

Although police haven't released a motive for Friday's killings, suspect Robert Louis Dear reportedly mentioned "baby parts" to investigators. He may have been drawing a connection to recent undercover videos related to Planned Parenthood's collection of post-abortion fetal tissue, which sparked a backlash against the group.

While attitudes in the U.S. have softened on many social issues, such as gay marriage and marijuana legalization, the abortion battle remains polarized both for politicians and for the American public. ​Americans who identified themselves as "pro-choice" held what Gallup called a "statistically significant" majority in May over Americans who described themselves as "pro-life." It was the first time since 2008 that ​pro-abortion rights supporters have held such a majority.

