The furor over Rep. Marjorie Taylor Greene's (R-Ga.) treatment of Rep. Alexandria Ocasio-Cortez (D-N.Y.) has sparked new worries that lawmakers could be in danger from their own colleagues.

Fears about growing incivility and polarization in American politics have been climbing for a generation. But the concern has reached a different order of intensity since the Capitol insurrection on Jan. 6, when members of Congress literally feared for their lives.

Greene’s encounters with some of her Democratic colleagues, along with a confrontation between a Greene staffer and Rep. Eric Swalwell (D-Calif.), show just how febrile the atmosphere on Capitol Hill has become.

In an exchange witnessed by The Hill’s Scott Wong on Friday morning, a Greene staffer challenged Swalwell over the Democrat wearing a mask. Swalwell retorted, “You don’t tell me what to f---ing do.”

Soon afterward on Twitter, Swalwell said Greene’s aide had attempted to bully him, adding, “I told the bully what I thought of his order. Predictably, he went speechless. I regret I wasn’t more explicit.”

Now there are calls for increased security, even as fencing near the Capitol remains in place since the days after the insurrection.

Democratic lawmakers who are less high-profile than Ocasio-Cortez are also expressing alarm.

Rep. Brendan Boyle (D-Pa.) told this column that there has been “a real, marked difference” in the atmosphere at the Capitol since the Jan. 6 attack.

“I have friendships on both sides of the aisle. But I have to say, even I really feel the tension,” Boyle said. “I have my own suspicions of certain colleagues of mine who are down the rabbit hole of conspiracy theory and egging on the insurrectionists — people that would literally want me dead.”

Republicans bridle at those kinds of remarks. But Boyle said that Jan. 6 marked the first time he had begun to seriously think about his own safety.

Like many public officials, he said he had no wish “to live in a cocoon” because of security fears. But in one example of heightened awareness, he said he now removes the lapel pin that identifies him as a member of Congress unless it is required.

Boyle freely acknowledged that others in his party are more likely to be targeted than he is. Asked whether fellow Democrats fear for Ocasio-Cortez’s safety, given her lightning rod status for conservatives, he replied, “As far as Alexandria or any other of my colleagues who seem to be the people who Fox News goes after — and none of them seem to be white males, coincidently, I’m sure — I do fear just a lone nut out there who goes down this rabbit hole, believes these conspiracies, believes the big lie.”

“It is a genuine concern. I have seen several of my colleagues have to walk around with security protection, and it concerns me. These are my friends and colleagues,” Boyle added.

Ocasio-Cortez’s office called for increased security measures after Greene followed her in the halls of the Capitol and began shouting at her on Wednesday. The exchange was witnessed by two reporters from The Washington Post, which first reported on the matter the following day.

Speaker Nancy Pelosi (D-Calif.) said Thursday that the House Ethics Committee ought to consider examining Greene’s conduct relating to Ocasio-Cortez, which she termed a “verbal assault.”

Greene for her part denies “screaming” at Ocasio-Cortez and says she was trying to engage the New Yorker in debate.

Greene’s innocent-sounding explanation sits incongruously with her past record. She at one time promoted the QAnon conspiracy theory — which she says she now regrets. She also expressed support on social media for a call to imprison or kill Pelosi.

On Friday morning, video emerged from February 2019 — before Greene was elected to Congress — in which she shouts through the mailbox of Ocasio-Cortez’s Capitol Hill office. 

In the now-deleted video, unearthed by CNN’s KFile, Greene warns that the New York congresswomen, first elected three months previously, is “bringing God’s judgement on our country.”

Greene also says, “You need to stop being a baby and stop locking your door and come out and face the American citizens that you serve.”

Ocasio-Cortez, asked about the video on Friday, told reporters, “This is a woman that’s deeply unwell and clearly needs some help.”

Some lawmakers are dismayed by the fact that a figure such as Greene draws so much publicity for her antics, a trend that they think devalues the actual work of legislating.

Rep. Marcy Kaptur (D-Ohio) worried that “the sophomoric tendencies of some have to be offset, and there just needs to be more attention on the serious work that Congress needs to do.”

But in a clear jab at Greene’s actions against Ocasio-Cortez, Kaptur also stressed that  “haranguing other members should not be allowed. It is uncivil behavior, and it is setting a very poor example to the nation.”

“Congress has always had show horses, work horses, and bullies,” Rep. Betty McCollum (D-Minn.) said in an email. “Most of us – Democrats and Republicans – are focused on doing the work. It’s called governing, and it is important.”

That dynamic is itself part of the problem. For years, the incentives in American politics — and much of the media coverage of it, especially on the right — have rewarded the most militant voices.

Former Speaker John Boehner (R-Ohio) wrote in his recent memoir of his dismay in realizing that a number of colleagues were more interested in cable news appearances than legislating — and that they could derive real political power from those appearances.

The pattern cannot be disentangled from the influence of former President Trump, who horrified his critics throughout his political rise by his propensity for insults and vulgarity — and, in doing so, delighted the Republican base, won a primary against numerous more seasoned GOP opponents and ultimately won the White House.

In an age less polarized and less driven by social media, it’s easy to imagine a figure such as Greene lingering in obscurity. Instead, she got more than 220,000 votes in winning her election last year. She is also a formidable fundraiser.

Allan Lichtman, a history professor at American University, condemned the media tendency to portray both parties as equally culpable for the current poisonous political tone.

Polarization “has gotten much worse, and if there was one phrase I would eliminate from the English language, it is ‘both sides,’” Lichtman, a longtime Trump critic who 15 years ago sought a Democratic Senate nomination in Maryland, said. “It is not both sides. It is coming overwhelmingly from one side, and that one side is the Donald Trump Republicans.” 

But even now, the former president retains a firm grip on the party, as was displayed in Rep. Liz Cheney’s (R-Wyo.) ouster from leadership earlier this week.

The idea that Jan. 6 was going to mark a turning point, after which American politics would walk itself back from the abyss, seems increasingly unlikely.

Meanwhile, the atmosphere of life on Capitol Hill just gets worse.

“You look at what Trump unleashed and what you see online,” Boyle lamented. “We don’t see the same kind of hate spewed in most other Western democracies. You don’t see in the Republic of Ireland or France or Germany members of their parliamentary bodies having to be escorted by police because there are threats directed toward them.”

The Memo is a reported column by Niall Stanage.