WASHINGTON — There are 99 legislators in the Tennessee House of Representatives, the body that voted on Thursday to expel two of its Democratic members for leading an anti-gun protest in the chamber.
Sixty of them had no opponent in last November’s election.
Of the remaining House races, almost none were competitive. Not a single seat flipped from one party to the other.
“We’re just not in a normal political system,” said Kent Syler, a political science professor and expert on state politics at Middle Tennessee State University in Murfreesboro. “In a normal two-party system, if one party goes too far, usually the other party stops them. They put the brakes on.”
In Tennessee, he said, “there’s nobody to put on the brakes.”
And not just in Tennessee.
Nationwide, candidates for roughly four of every 10 state legislative seats run unopposed in general elections.
And across the country, one-party control of state legislatures, compounded by hyperpartisan politics, widespread gerrymandering, an urban-rural divide and uncompetitive races, has made the dysfunction in Tennessee more the rule than the exception.
The lack of competition means incumbent lawmakers face few consequences for their conduct. And their legislative actions are driven in large part by the fraction of partisans who determine their fates in primary elections, the only political contests where they face serious opposition.
Those forces, intensified by the Supreme Court’s open door for gerrymandering and the geographic sorting of Democrats into urban areas and Republicans into rural ones, are buffeting legislatures run by both parties: Republicans have total control of legislatures in 28 states (including Nebraska, which is nominally nonpartisan) and Democrats in 18.
That control has enabled both parties to enact legislation advancing their policy agendas, as would be expected, especially at such a partisan moment. Both parties, to differing degrees, have abused their ability to gerrymander.
But it is Republican-run states, many experts say, that are taking extreme positions on limiting voting and bending or breaking other democratic norms, as Tennessee did in expelling two lawmakers last week.
Before Thursday, there had been only two expulsions from the Tennessee House since the Civil War.
Steven R. Levitsky, a Harvard University government professor and the author with Daniel Ziblatt of the book “How Democracies Die,” said one-party rule in Democratic states like Illinois has typically led to corruption and abuses of power.
But states controlled by Democrats, he said, have not tried to limit voting, restrict civil liberties or push back on democratic norms the way Republican-controlled states have in recent years.
“Only one party, I think, is flirting with authoritarianism right now,” Professor Levitsky said.
Republican leaders in Tennessee said they had expelled the Democratic lawmakers not just for last week’s protests but also for a pattern of grandstanding and disruptions that they said was the real assault on the ability of the legislature to function democratically.
“My people deserve to be heard as well, and you can’t have that with folks in the well with a bullhorn,” Representative William Lamberth, a member of Republican leadership, said after the expulsions. Since then Representative Justin Jones of Nashville and Justin Pearson of Memphis have been reinstated by their local governing boards ahead of special elections later this year.
Victor Ashe, a Republican and former mayor of Knoxville who served in the legislature when Republicans were a minority in the 1980s, said the legislature had become more contentious and his party more extreme since then. In the heat of partisan combat, he said, “some people don’t think about ‘This is not democracy.’
Referring to Republicans and some Democrats in the legislature, he said: “They just have a different mind-set. Once you’re elected, the idea that your opponent doesn’t have to be your enemy seems to have vanished.”
The expulsions come at a time when the legislatures in Tennessee and other states have pushed at the traditional limits of political power.
In Tennessee, which was previously known for its relatively moderate, pragmatic political culture, the legislature took aim at the state’s center of Democratic support: Republican lawmakers created a gerrymander last year that split Nashville’s Democratic-held congressional district, which has represented the city since Tennessee became a state, into three — extending well outside the city and into typically Republican areas.
The legislature also unilaterally passed a law cutting the size of Nashville’s metropolitan council in half, to 20 members from 40, but a judicial panel temporarily suspended the action on Monday.
Elsewhere, Republican-led legislatures in North Carolina and Wisconsin passed laws stripping power from incoming Democratic governors after Roy Cooper was elected in North Carolina in 2016 and Tony Evers in 2018.
In Missouri, the legislature is trying to take over the police department in St. Louis, one of several moves aimed at leaders of Democratic cities. Many of those actions explicitly revoke cities’ longstanding authority to enact local laws that might run counter to G.O.P. legislation on priority issues like L.G.B.T.Q. rights, law enforcement or guns.
Republican legislatures in Ohio, Arkansas, Florida and several other states are considering actions this year that would limit the ability of citizens to get ballot initiatives before voters, particularly on issues like abortion and gerrymandering. Enacting barriers to voting — broadly aimed at young voters and members of minority groups that lean Democratic — has become part of the standard Republican playbook.
Still, Mr. Ashe said Democrats couldn’t blame Republicans for their plight in red states, having lost the ability to compete for much of the Republican electorate during the Obama years and after.
“Democrats are also culpable,” Mr. Ashe said. “They haven’t been able to find good people to run.” Tennessee Republicans built their majority, he noted, by fielding candidates even in contests where they were doomed to lose.
Jim Cooper, Nashville’s longtime Democratic representative in Congress, said he agreed. “Local Democrats have done a terrible job in recent decades,” said Mr. Cooper, who represented Nashville for 20 years before retiring in January after the legislature gerrymandered his district. “We’re not good at fighting back. For example, we didn’t go out and recruit anti-Trump Republicans, because we liked having a small tent.”
That sorting into political tribes, where party loyalty is more important than local or state issues, has only cemented one-party control in state legislatures. In sharp contrast to past decades, “it’s pretty much what a voter thinks of the president that is going to dictate how a voter casts their ballot in a state legislative election,” said Steven Rogers, a Saint Louis University political scientist who has studied the issue. “What legislators do themselves doesn’t really matter that much anymore.”
There’s another reason state legislators in Tennessee — and many other states — so often face no opposition: Few people want to run, or can afford to.
At an annual salary of $24,316, “it’s like a nothing job,” said Mr. Cooper, the former congressman. “It can ruin your day job.”
“The sad reality is that good people don’t want to run for office anymore,” he said. “So we shouldn’t be surprised by what we get when the fringe 10 or 15 percent of the state legislature can run everything.”
Still, some political experts and Nashville voters said the expulsion debacle had the potential to reboot some competition. Most pointed to the wave of national publicity that elevated the two expelled Democrats to national figures and reinvigorated — if only briefly — the party’s political energy.
“If there’s any hope for the state Democratic Party living again, it’s going to come from a rejection of that sort of inevitability of extremist control” on issues like the mass shooting in Nashville, said Keel Hunt, a political columnist and a former top aide to Lamar Alexander, the former Tennessee Republican governor and senator.
Courtney Taylor, 33, a Nashville native, lives in the district represented by Mr. Jones and voted for him in part because of his advocacy for social justice issues. For all the pain of the past week, she said, she was glad that for a few days at least he was able to shake up the legislature’s status quo.
“There has been this whirlwind of stress,” she said. “A lot of people are feeling like they have their hands tied. There is a sense of helplessness and frustration.” She said it was important to force the legislature to listen.
“It makes you feel a little less alone and a little less like you are screaming into the void to have someone actively take notice and stand with you.”
Jamie McGee and Emily Cochrane contributed reporting from Nashville. Research was contributed by Susan Beachy, Kitty Bennett, Jack Beggs and Alain Delaqueriere.