A man firebombed the home of Pennsylvania Gov. Josh Shapiro in April, hours after the governor and his family hosted more than two dozen people to celebrate the first night of Passover. The suspected arsonist targeted the governor because of "what he wants to do to the Palestinian people," according to police records. Two weeks ago, a man shot and killed a young couple outside the Lillian & Albert Small Capital Jewish Museum. "Free Palestine," the man shouted. "I did it for Gaza," he later told investigators. Then, on June 1, a man hurled Molotov cocktails at a peaceful gathering of pro-Israel demonstrators in Boulder, CO. Hurling abuse at the crowd, the attacker shouted "Free Palestine" as he set fire to several people,includingan 88-year-old Holocaust survivor. These violent attacks come after years ofescalating rhetoric, protests and demonstrations against the ongoing war in Gaza. A reportreleased last monthfound that antisemitic incidents across America hit a record high for the fourth year running last year, and the same researchers worry that trend will continue throughout 2025. The recent wave of attacks has Jewish communities across the countryon high alert. And it has experts and analysts who study extremist movements concerned the antisemitism that has already flooded online spaces and infested someprotests on college campusesand elsewhere could now be entering a more deadly phase. "The Jewish community is used to having bulletproof glass and metal detectors at their institutions, but this was a public gathering," The ADL's Senior Vice President of Counter-Extremism and Intelligence Oren Segal told USA TODAY of the Boulder attack. "The Jewish community is now concerned about being publicly Jewish." Antisemitic violence is, of course, not new in America. The deadliest anti-Jewish attack in U.S. history occurred just seven years ago, in 2018, at the Tree of Life synagogue in Pittsburgh, where 11 people were shot and killed and six more were injured. The country also saw periods of antisemitic violence in the 1980s and 90s, including bombing attacks and targeted assassinations by a white supremacist group. While the new wave of violence certainly appears to have been inspired by the war in Gaza, there are notable differences between the attacks in Washington, D.C. and the one in Boulder, said Javed Ali, senior director for counterterrorism at the National Security Council in 2017 and 2018. The suspect in the Washington D.C. shooting had recently been involved in leftist politics and protesting, but the suspect in the Colorado attack had spent more than a year planning his assault, and doesn't appear to have been involved in the protest movement, Ali said. "We've seen these waves of antisemitic violence throughout modern U.S. history," Ali said. "Is this now presenting another one of these kinds of waves? Hopefully it doesn't get bigger than these two attacks." In both the Washington attack and the assault in Boulder, the perpetrators shouted about the war in Gaza. Mohamed Sabry Soliman, the suspect in the Boulder attack, said he specifically targeted the group because of its pro-Israel stance and stated he "would do it again," according to a court filing from the FBI. Ali said it stands to reason that the more people who are angry about the war, the more likely it is that some will become radicalized and, in turn, that some will take violent action. That's typically how social movements spawn violent domestic extremists, Ali said. It's essentially a numbers game. "If there's a bigger pool of people who are radicalized, then potentially that increases the probability that there will be a smaller number of people who funnel from that larger pool of radicalization into the violent action, and maybe, maybe that's what we're seeing now," he said. The ADL's Segal put it differently. He said the protest movement has consistently and unfairly blurred the lines between the actions of the Israeli government and the Jewish people at large. Violence like the recent attacks is the inevitable result of that bias, he said. "When you have 600-plus days of rhetoric that is not just about opposition to Israeli government policy, but that often features language that dehumanizes Israelis, Zionists and Jews, it creates an atmosphere in which these plots and attacks are much more likely," Segal said. The events in Colorado and Washington and the arson fire at the Pennsylvania governor's mansion in April are part of a pattern in which anti-Israel sentiment is used as a justification for antisemitic violence, said Halie Soifer, chief executive officer of the Jewish Democratic Council of America, a Washington-based group that calls itself the voice for Jewish Democrats. "We see a deeply troubling pattern, and it has shattered a sense of security that we should have as American Jews," Soifer said. Synagogues and other Jewish establishments increased their security after the Tree of Life shooting. Ever since that attack, people entering synagogues typically go through security measures similar to TSA airport checkpoints, Soifer said. "You go through a mag, and there is a device to check bags," she said. But the recent attacks have been largely outdoors, which requires another layer of security that wasn't necessarily needed before. Groups are now considering how to create larger perimeters around Jewish institutions and gatherings, she said. "This has created a crisis in terms of every Jewish American rethinking their security," Soifer said. "It's devastating to think we're at a point where that's needed. But we are." Students at the University of Denver were already concerned about the rise of antisemitic violence across the country, said Adam Rovner, director of the university's Center for Judaic Studies. The attack on the marchers in Boulder heightens their fears, he said. "Some people feel frightened. Some people feel angry," Rovner said. "Some people feel resolute and a sense of solidarity." Rovner said when he went to synagogue on Sunday, members of the congregation were warned not to mill around outside the building because it was the Jewish holiday of Shavuot and there were fears of an attack. Since the attack on the marchers in Colorado, "there is just a real awareness that Jewish events are requiring extremely high levels of security all the time, and there is a very strong awareness that Jews are targets," said Rachel Harris, director of Jewish Studies at Florida Atlantic University. There is also a growing concern that the public tends to normalize terrorism against Jews by attributing it to political protest, Harris said. "Any other group that is targeted by acts of terrorism, we call them acts of terrorism," she said. "We don't try and normalize that. This continued refrain that says, well, they shouted 'free Palestine,' so it was really a political gesture, is really disturbing." Everyone has the right to protest and peacefully voice their opinion, Rovner said. "There are certainly horrors that the Palestinians are suffering," he said. "There are certainly horrors that Israelis and Jews are suffering. They don't cancel each other out. They both exist. The people who can't seem to contain two conflicting opinions in their mind at the same time are the ones who lash out violently. They are simple minded, idealized." Twenty-four hours after the attack in Boulder, Lisa Turnquist returned to Pearl Street to lay flowers and a small Israeli flag at a small memorial. Police say Mohamed Sabry Soliman, an Egyptian immigrant who overstayed his visa, threw Molotov cocktails at the marchers while yelling "Free Palestine." Twelve people, ages 52 to 88, suffered burn injuries ranging from serious to minor. Turnquist, 66, said she'd been a regular attendee at the Sunday marches, rain snow or shine, in which participants call for Hamas to release the Israeli hostages it is holding in Gaza. She was just arriving on June 1 when she saw flames on a woman's legs. Turnquist, who is Jewish, said she grabbed a towel from her dog Jake's stroller and used it to smother the flames on the elderly woman's legs. Turnquist said she started participating a few weeks after the marches began following the October 2023 attack by Hamas on Israel. Her voice alternately tearful and angry, she recounted how week after week the walkers have been confronted with allegations that they are complicit in genocide for demanding Hamas release its hostages. "We just want them home, and that's why we do this," she said. The morning after the attack, she woke up and didn't want to get out of bed. But she did. "This is when we have to get up and stand up," she said, "and we have to push back." Contributing: Trevor Hughes This article originally appeared on USA TODAY:Violent antisemitic attacks mark new phase in anti-Israel protests