Sgt. Brad Sevier conducts a traffic stop along Interstate 70 in St. Louis. “I don’t see how it can be detrimental having more law enforcement in an area that really needs more policing,” he said. (Whitney Curtis/For The Washington Post)

Sgt. Brad Sevier usually patrols an area of Missouri where there is one farm for every 20 residents. Now the Missouri state trooper commutes an hour to patrol the big city.

On orders from Republican Gov. Eric Greitens, Sevier and about two dozen troopers have laid claim to St. Louis highways that slice through some of America’s most dangerous neighborhoods, a move that has sparked concern among residents wary of heavy policing. It’s the first time in decades that state troopers have patrolled the city, Greitens said.

“We are looking for anything,” Sevier said shortly before pulling over a motorist for an expired license plate near downtown. “I don’t see how it can be detrimental having more law enforcement in an area that really needs more policing.”

Greitens dispatched the Missouri Highway Patrol last month amid a surge in shootings and assaults in St. Louis, part of a nationwide trend of rising violence in some large cities. The killings have rattled neighborhoods and embarrassed city officials, who tend to be Democrats. But now governors — who tend to be Republicans — are sending in their troops to fight urban crime, reopening historical tensions.

The governors’ actions mirror President Trump’s vow to send in federal agents to curb crime in Chicago, which he said in June had reached “epic proportions.”

“Today, we declare that the days of ignoring this problem are done,” said Greitens, a former Navy SEAL and competitive boxer, announcing his plan last month to send in state patrolmen to look for criminals in St. Louis. “We are rolling up our sleeves and taking strong action to protect people.”

Lyda Krewson, the new Democratic mayor of St. Louis, has fierce political disagreements with Greitens on many issues, including gun control and the funding of social services. But Krewson also has an intimate perspective of the city’s crime problem: In 1995, she saw her husband fatally shot during an attempted carjacking in front of their home in the city’s Central West End.

Krewson supports Greitens’s plan.

“There are a lot of guns on these highways. There are a lot of drugs on these highways,” Krewson said. “As long as it’s done in a responsible way — and I don’t have any reason to believe it won’t be — I think it’s a good help.”

But in an era of increasingly polarized views on policing, Missouri’s intervention is unsettling some local residents who question the governor’s strategies and tone. How elected leaders define a “gang,” use the word “criminal” and deputize outside law enforcement agencies are emerging as flash points. The debate threatens to drive another wedge between some officials in heavily Democratic cities and GOP leaders in statehouses and in Washington.

“He was heard saying . . . ‘Let’s go get them,’ ” said state Rep. Michael Butler, a St. Louis Democrat who was referring to an offhand, salutatory remark Greitens made while rallying Missouri troopers. “A lot of folks wonder who ‘them’ is, and what exactly did he mean.”

St. Louis has recorded more than 110 homicides so far this year, which, as of late July, put 2017 on pace to be the city’s deadliest year in more than two decades. The trends have been similar in big cities from Baltimore and Nashville to Tulsa and Little Rock, and in response, governors are reviving a role many had embraced from the 1960s through the early 1990s but pulled back from as homicide rates declined.

Last month, after 25 people were shot in a nightclub not far from the governor’s mansion in Little Rock, Arkansas Gov. Asa Hutchinson organized state troopers and FBI agents to respond to “a looming cloud of violence” in that city.

In Texas, Gov. Greg Abbott pledged in spring to use “all lawful means” to snuff out what he called a serious “gang problem” in Houston, the state’s largest city.

In South Carolina, Gov. Henry McMaster even used warlike language when announcing his plan for more state resources in Myrtle Beach, where homicides in June threatened the city’s reputation as a family-friendly beach destination.

“There will be a lot more boots on the ground,” McMaster said in deploying state troopers.

The governors are all Republicans, and their actions come as Trump has used tough-on-crime rhetoric in response to law enforcement concerns, most recently telling officers in a speech not to “be too nice” to suspects. Jim Pasco, past executive director and current senior adviser to the president of the National Fraternal Order of Police, said GOP governors know that crime “has been a good issue” for Trump.

“It resonates with the people who elected him,” said Pasco. “The governors see the reaction he is getting, and it spurs them to action.”

But the implementation of the state response can clash with local policing strategies. Some on the left fear a shift away from Obama-era initiatives such as community policing, fewer mandatory minimum sentences and limits on the militarization of police units.

The tension is particularly pronounced in St. Louis, where the 311,000 residents are still navigating the aftermath of the 2014 police shooting of Michael Brown in Ferguson, Mo., a close-in suburb.

For now, Greitens’s proposal is fairly limited. For the first time in decades, Missouri state troopers will patrol four major highways in St. Louis, freeing up city police to focus on violent crime that has driven up the homicide rate.

After seven people were fatally shot here over Father’s Day weekend, Greitens decided it was time to act, despite accusations from the community that he is grandstanding to bolster his macho political image.

During his campaign last year, Greitens shocked pundits by airing television commercials showing him firing military-style assault rifles. His ads included him saying he was going to “take back Missouri” and “fire away” for reforms.

(Eric Greitens)

Shortly after he was elected, Greitens experienced St. Louis’s crime woes personally when his wife was robbed at gunpoint as she left a restaurant.

“We go out and do what is necessary to save lives,” Greitens, an Iraq War veteran and Purple Heart recipient, said in an interview. “This is tearing cities apart.”

His critics, however, accuse Greitens of using St. Louis as a punching bag by vilifying a city that is about 50 percent African American and has a 25 percent poverty rate.

“You got a governor who is probably looking to his next move, so he has got to play to his base,” said Sarah Wood Martin, a St. Louis alderwoman. “And to them, it looks nice sending in the state troopers to get control of what is made to look like an out-of-control urban area.”

Beside politics, activists say there is real fear that Greitens’s plan could lead to more racial profiling. African Americans in Missouri are already 75 percent more likely to be stopped while driving than white motorists, according to the data compiled by the state attorney general’s office.

“Until and unless we start talking about that, there is a concern we are going to get more of the same,” said Jeffrey A. Mittman, executive director of the American Civil Liberties Union of Missouri, which is seeking state records clarifying how the enhanced state patrols will be carried out.

While looking for expired license plates, unregistered vehicles or speed violators, Sevier stopped a white woman who was arrested for an outstanding warrant for failure to appear in court on a previous traffic citation.

“Traffic enforcement is a good tool in finding criminals,” said Sevier, who had been assigned to Perry County in Missouri’s southern river delta. “That lady was wanted for expired registration but it just as easily could have been a murder warrant or a robbery warrant.”

During the first 11 days of the state patrols on about 16 miles of interstate highways that had been only lightly patrolled before, troopers issued more than 900 traffic tickets and made 220 arrests, according to Missouri Highway Patrol data.

St. Louis resident Danielle Shanklin panned Greitens’s plan. Her 25-year-old sister, Sigaria, was fatally shot in the head last summer when gunmen opened fire on a car she was in. Shanklin’s 3-year-old son, who was riding in the back seat, was unharmed.

Greitens’s initiative, she said, is nothing more than a way to “give out more tickets for speeding.”

“What they need do is add more funding to do things in the community,” Shanklin said, reflecting a widely held view in St. Louis that Greitens can’t fight crime and cut spending on social programs at the same time.

That community reaction, both here and in other cities targeted by governors, is putting mayors in a bind as they decide whether to embrace the help and, if so, how publicly.

In Arkansas, Little Rock Mayor Mark Stodola (D) supported Hutchinson’s plan but followed up on the governor’s announcement with his own one-hour news conference to call for more investment in inmate reentry programs, job training and neighborhood redevelopment.

“We know we cannot arrest our way out of this problem,” Stodola said.

Darrel Stephens, executive director of the Major Police Chiefs Association, said the true test of the governors’ initiatives will come in a few months.

“The real problem with this is usually the states can’t stay very long,” said Stephens, noting states’ limited budgets as well. “And to be effective at policing locally, you just can’t jump in and then take off two or three months later.”

Correction: An earlier version of this article misidentified Mayor Lyda Krewson’s neighborhood. The article has been updated.