Part of Kristina Romero’s job as the regional director for several reproductive health clinics in the South, some of which offer abortion services, is to drive one of the clinic doctors to and from work. That way anti-abortion extremists can’t identify the doctor’s car.

One day, as Romero left her home, she saw a big poster with the doctor’s picture in a bullseye. There were more: The posters started in front of her house and continued along the entire route she took to get to the clinic.

To Romero, the posters were not only threatening to the doctor, but also to her. That they lined her route to work was a clear sign that anti-abortion extremists had followed her. The message, she explained, “was for me to be scared. It was for me. There’s nothing in my experience with the protesters that stands out more than that morning when I got up to go get the doctor and saw the doctor’s picture all over town.”

This is just one example of what abortion providers face in America today. Anti-abortion extremists who engage in such threatening behavior — and too often, the media outlets that cover them — consider it part of protest of the larger issue of abortion. But these targeted threats are forms of terrorism that are meant to scare providers into stopping the provision of abortion services. As one provider told us, such tactics go “beyond bullying. It’s this extreme bullying and intimidation and harassment,” which creates a “culture of terror” among providers.

To call anti-abortion extremism domestic terrorism may seem surprising, but that is the conclusion of our new book, “Living in the Crosshairs: The Untold Stories of Anti-Abortion Terrorism.” It’s a conclusion we reached after analyzing 87 interviews with abortion providers from 2011 to 2014 about their experiences being the targets of anti-abortion extremists. According to the Feminist Majority Foundation, in this time period, this kind of individual targeting has substantially increased.

And yet, to call such acts terrorism is immensely controversial. In fact, anti-abortion terrorism has been almost completely absent from the renewed national conversation about domestic terrorism spurred by last month’s church shooting in Charleston, South Carolina.

Crystalizing this controversy, in early 2009, the Department of Homeland Security (DHS) actually reached the conclusion that anti-abortion extremists were terrorists in two reports. But in the face of strong backlash from many different constituencies, including anti-abortion groups, DHS caved to public pressure and pulled both reports less than two months after they were released, claiming they were inadvertently released before being fully vetted.

The first DHS document, titled “Domestic Extremism Lexicon (PDF),” sought to define “key terms and phrases” in the effort to combat “the threat that domestic, non-Islamic extremism poses to the United States.” Among the terms was “anti-abortion extremism.”