The methods of the extremists vary greatly. Some pregnancy centers were only lightly vandalized with slogans, such as "Jane was here," "You're anti-choice, not pro-life" and, more frequently, threats of future violence like "If abortions aren't safe, neither are you." (Related: Abortion militants are firebombing pro-life centers across America and the media pretends like nothing is happening.)
In other pregnancy centers, extremists have thrown Molotov cocktails and committed arson, thrown rocks, bricks and bottles through windows and doors and otherwise damaged property and threatened violence against pregnancy resource center employees.
In some attacks, pro-abortion extremist organizations like Jane's Revenge and the Anti Hope Brigade have taken responsibility. In others, the attackers remain anonymous and could be extremist individuals or small groups with no formal affiliation to any anti-life domestic terrorist organization.
Pregnancy resource centers in at least 12 states and the District of Columbia have so far been attacked. These states are California, Florida, Iowa, Maryland, New York, North Carolina, Oregon, Pennsylvania, Texas, Virginia, Washington and Wisconsin.
Jane's Revenge warned that it will not confine its attacks to resource centers. The group considers banks, businesses and even churches that support pregnancy centers as responsible for "the violence of forced birth" and warned that they may be the targets of future attacks.
"We are all over the U.S., and we will issue no further warnings," wrote Jane's Revenge in its letter claiming responsibility for one of the first attacks against a pregnancy resource center in Wisconsin. "We will not stop until … the inalienable right to manage our own health is returned to us."
Political analysts and other academics have noted that violent tactics are usually not successful.
Omar Wasow, assistant professor of politics at Pomona College in California, used the civil rights movement of the 1950s and 1960s as a prime example of this.
Wasow has researched the political consequences of different kinds of political actions during that period, violent and nonviolent. He found that violent protests had the effect of chilling support for the movement, leading to more votes for conservatives. Peaceful protests, meanwhile, had the effect of garnering more support from moderate voters.
"Even if we think violence might be justified in response to state repression under segregation, or Jim Crow, it may produce outcomes entirely contrary to what activists were fighting for," said Wasow. "Norm-violating tactics can be repulsive to put to potential moderate allies."
Mary Ziegler, a law professor at the University of California, Davis and a scholar on the abortion rights movement, believes the same effects can already be seen. The pro-life movement, she noted, was responsible for its own acts of violence in the past against abortion centers. But these attacks quickly disappeared when the movement learned that it was not effective.
"I don't think that violence was particularly effective for conservatives," said Ziegler. "It's not wrong to say that progressives need to be willing to use the strategies that conservatives have used. But committing illegal acts of violence has not historically been why the [pro-life] movement has succeeded."
Ziegler noted that the pro-life movement has been working for nearly 50 years to get Roe v. Wade overturned. They did this through legal means and by focusing on making long-term, structural changes.
"People often focus on a narrow period of time and say, 'Oh, look at how all of this success was made [in a small period],'" said Ziegler. "But there's really decades of activism that's slowly building the kind of social and political capital to make change happen."
Read more stories about the attacks by pro-abortion groups at Abortions.news.
Watch this episode of the "Health Ranger Report" as Mike Adams, the Health Ranger, talks about how the Left reacted "with demonic anger and violence" to the news that Roe v. Wade might be overturned.