In the wake of a school shooting in Nashville that left six people dead, three Democratic lawmakers took to the floor of the Republican-controlled Tennessee House chamber last week to rally for stricter gun control.

On Thursday, two of the lawmakers, Representatives Justin Jones and Justin J. Pearson, were expelled from the House, a dramatic act of political retribution. But the third lawmaker, Representative Gloria Johnson, survived, shocking some Democrats: The chamber voted 65 to 30 to remove her, falling one vote short of the two-thirds majority needed in the 99-seat chamber.

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Hundreds of students, parents and teachers have marched to the State Capitol since the Covenant School shooting on March 27 and have held demonstrations at the Capitol to demand action by the legislature to toughen gun laws.

Last Thursday, Representatives Jones, Pearson and Johnson — whose districts are in Nashville, Knoxville and Memphis, the state’s three largest cities — interrupted the legislature by chanting “No action, no peace” on the House floor. Legislative proceedings were forced to a halt.

The speaker of the House, Cameron Sexton, responded by comparing the three lawmakers to the rioters who breached the U.S. Capitol in 2021. He called their actions “unacceptable” and a violation of House rules of decorum and procedure. By Monday, he had revoked their ID access to the State Capitol building and had stripped two of the three lawmakers of their committee assignments.

The protests over gun policy have continued. Demonstrators flooded the building again on Thursday morning before the expulsion votes, with loud chants of “Gun control now” and “Not one more” outside the House chamber. Inside, dozens of protesters held up fists and signs in support of gun control and the three Democrats, but they remained silent to avoid being ejected from the galleries.

The Republicans who control state government, led by Gov. Bill Lee, have rejected the calls for tighter gun laws and have largely focused instead on toughening school security. The Tennessee House passed a bill on Thursday that would require schools to conduct annual drills, keep all entrance doors locked and install a mobile panic-alert system.

The three Democratic lawmakers spoke out against the measure on Thursday, with Mr. Jones calling it a “white flag of surrender” that does not address the root causes of gun violence.

Ms. Johnson, who represents parts of Knoxville, is the most senior of the three; she was first elected to the House for the 2013-2014 term. A former teacher, she was elected again in 2018. After redistricting following the 2020 census, she moved to avoid having to contest the seat of another Democratic member.

Mr. Jones, 27, was one of the youngest members of the House before his expulsion on Thursday. He won election in November to represent parts of Nashville. A graduate of Fisk University in Nashville, he made a name for himself locally as a community organizer. He has held sit-ins in the State Capitol and, in the summer of 2020, led a 61-day protest against racial injustice outside the building that included demands for the removal of a bust of a Confederate general.

Mr. Pearson, 28, won a special election by a landslide in January to represent parts of Memphis. A native of the city and graduate of Bowdoin College in Maine, he is the son of an educator and a preacher. Mr. Pearson gained prominence when he successfully opposed a crude oil pipeline proposed for South Memphis.

In interviews, all three lawmakers spoke of how gun violence — and in some instances, their personal experiences of it — had helped shape their paths to politics. Mr. Pearson recounted the pain of losing family members and a mentor to gun violence, and said the push for tighter restrictions on firearms “is personal when you lose your friends, when you lose loved ones.”

Mr. Jones recalled attending his first protests after Trayvon Martin, a 17-year-old Black teenager, was shot by a neighborhood watch volunteer in Florida. “This issue is something that has been a part of our generation,” he said. “This is a very personal issue.”

Ms. Johnson recalled a shooting at Central High School in Knoxville that took place while she was still working as a teacher, and “the terror on the kids’ faces as they were running down that hill into my classroom.”

Three Republican state representatives — Andrew Farmer, Gino Bulso and Bud Hulsey — filed individual resolutions on Monday to formally expel each of the three Democrats. Hours later, a procedural vote easily cleared the chamber, despite Democratic opposition.

In each resolution, Republicans charge that the lawmaker “did knowingly and intentionally bring disorder and dishonor” to the House and “generally engaged in disorderly and disruptive conduct.” The measures do not cite any other consequence of the protests.

A two-thirds vote of the 99-seat House is required to expel a member. The Republicans have the necessary supermajority to pass the expulsion resolutions.

On Thursday, the House voted to oust Mr. Jones and Mr. Pearson. Ms. Johnson survived: The chamber voted 65 to 30 to remove her, falling one vote short.

Special elections would be held to fill the seats of the expelled lawmakers. Mr. Jones and Mr. Pearson will be able to run again in the elections and be re-elected to their seats.

Local governing bodies in each district can appoint temporary representatives — who could even be the expelled lawmakers themselves — to hold the seats until the special elections are held. Multiple members of the Metropolitan Council, which oversees Nashville, have pledged to nominate Mr. Jones to his seat as a temporary appointee.

Expulsions of lawmakers from state legislatures have been rare in American history.

Six lawmakers were expelled from the Tennessee House in 1866, immediately after the Civil War, for seeking to prevent the ratification of the Fourteenth Amendment, which granted citizenship to formerly enslaved people. Since then, the House of Representatives in Tennessee has voted only twice to oust a lawmaker. Both votes were bipartisan: in 1980, after a sitting lawmaker was convicted of soliciting a bribe, and in 2016, after the House majority whip faced allegations of sexual misconduct while in office.

Across the country, most expulsion cases have involved state lawmakers who faced criminal charges or accusations of sexual misconduct. An Arkansas lawmaker, Mickey Gates, was expelled in 2019 for failing to pay taxes; a Colorado lawmaker, Steve Lebsock, was expelled in 2018 after facing multiple allegations of sexual harassment.

In 2021, a four-term Republican lawmaker, Mike Nearman, became the first person ever expelled from the Oregon House after he let armed demonstrators into the locked State Capitol and was charged with official misconduct.

That same year, the Ohio House expelled Larry Householder, who had been arrested and charged in a $60 million corruption scheme while serving as House speaker. It was the first time an Ohio lawmaker had been expelled since 1857, when a member was removed for punching another member.

In 1920, the New York State Assembly expelled five Socialist lawmakers — the party’s entire delegation. No other lawmaker was expelled in the state for nearly a century, until the State Senate expelled Hiram Monserrate in 2010 after he was convicted of misdemeanor assault.

Sheelagh McNeill contributed research.