It started with a plea from the Republican governors of Texas and Arizona.

“We respectfully but urgently request that you send all available law enforcement resources to the border in defense of our sovereignty and territorial integrity,” Gov. Greg Abbott of Texas and Gov. Doug Ducey of Arizona wrote June 10 in a letter to other governors.

Their Republican colleagues in multiple states, including Florida, South Dakota, Iowa, Nebraska, Arkansas and Idaho, heeded the call, announcing that they are sending state troopers or National Guard troops to the border.

It’s unclear what these out-of-state forces will be empowered to do, and some states aren’t offering much detail. Based on what we’ve gathered, they will be limited to investigative work and backing up highway patrols

Abbott and Ducey say that they were prompted to act because the Biden administration’s “failure to enforce federal immigration laws causes harms that spill over into every state,” such as drug smuggling.

U.S. Customs and Border Protection says southwest land border encounters for fiscal year 2021, which includes the end of Trump’s term and Biden’s tenure so far, are up compared with the past few years. (Encounters data refers to events, not people, so a person making multiple attempts to cross the border would be counted more than once.)

Homeland Security Secretary Alejandro Mayorkas said in March that the U.S. is “on pace to encounter more individuals on the southwest border than we have in the last 20 years.”

National Guard personnel have been deployed to the border in the past under the orders of Presidents George W. Bush, Barack Obama and Donald Trump, but it is far more unusual for a governor to request personnel from faraway states to help at the border.

A CBP spokesperson said the federal agency will continue to leverage its longstanding relations with state and local law enforcement, but referred questions about Texas’ move to state officials.

Tasks include help with drug interdiction investigations, vehicle maintenance

During the past few months, Abbott and Ducey have taken a series of steps in response to illegal immigration at the border. On May 31, Abbott declared a state of disaster and directed law enforcement to help prevent criminal activity. The state has deployed 1,000 state troopers and 500 National Guard members, according to the Migration Policy Institute.

In June, Abbott announced that he would use $250 million in state funds and crowdsourced private funds to continue to build barriers along the border.

Arizona has also sent state troopers and National Guard forces to its own border with Mexico.

Abbott and Ducey made their request to states through the Emergency Management Assistance Compact. The compact, which was ratified by Congress in 1996, is a partnership among all the states to provide mutual aid in times of emergencies, historically for disasters such as hurricanes or wildfires. The compact’s website did not list border enforcement as a past use by the states.

The states that responded are offering limited information about what tasks their forces will handle.

A spokesperson for the Florida Department of Law Enforcement, Gretl Plessinger, told us that assignments would vary daily based on needs but that agents and analysts are working investigations associated with human smuggling, drugs and weapon smuggling. Each Florida agent is paired with one from Texas.

Plessinger said that Texas has provided Florida officers with arrest powers through the compact but “we aren’t enforcing immigration laws.”

Arkansas National Guard Members will be under operational control of the Texas National Guard and help with vehicle maintenance. Arkansas will cover personnel and travel costs for an estimated 20 to 30 people, while Texas will cover lodging.

“These are all verbal agreements at this point as we are early in the coordination and planning process,” said Shealyn Sowers, a spokesperson for Arkansas Gov. Asa Hutchinson.

Idaho will send five state troopers on a 21-day mission starting July 6 to help Arizona State Police with intelligence gathering and investigative work related to drug interdiction at the border. The troopers will have the same authority given to Arizona state troopers.

Federal government has tapped states to help in the past

There is precedent for states to help the federal government with border issues, but their authority is limited, said Michele Waslin, program coordinator for the Institute for Immigration Research at George Mason University.

“State police and National Guard cannot enforce immigration laws; they cannot deport people, but they can assist the federal government,” Waslin said.

Jessica Bolter, an immigration expert at the Migration Policy Institute, said that in the past, state troopers have conducted surveillance and been tasked with making arrests to enforce anti-smuggling/trafficking laws. But arrests have more often taken place for more minor offenses, such as drunken driving and minor drug charges.

The four states that border Mexico — Arizona, California, New Mexico and Texas — have cooperated with the federal government in the past and devoted additional funding and resources to border enforcement.

For example, in 2006, they all signed pacts with the federal government to allow National Guard personnel to help patrol the border area and support federal efforts as part of Operation Jump Start.

In July 2014, then-Gov. Rick Perry ordered 1,000 Texas National Guard troops to the border in response to the influx of unaccompanied children. In 2010, Arizona’s then-Gov. Jan Brewer announced a border security plan that included National Guard reconnaissance, aerial patrolling and military exercises.

But the federal government has most of the authority to enforce immigration laws, and defines only a limited role for state and local police.

Federal law allows U.S. Immigration and Customs Enforcement to enter into agreements with state and local agencies and train officers to carry out civil immigration law enforcement functions. But state and local governments can participate only under federal supervision.

For criminal enforcement, Congress has authorized state and local police to arrest violators of two criminal immigration provisions: one barring smuggling and trafficking, and another targeting people who reenter the country illegally following removal, according to the Migration Policy Institute.

Still, state and local police powers are limited.

“First, they cannot stop individuals solely to inquire about their immigration status. There must be another primary reason to detain someone for violating a criminal statute. And the duration of detention cannot exceed what is necessary for criminal law enforcement purposes,” the Migration Policy Institute wrote. “And second, state and local authorities can detain someone they suspect of illegally reentering the United States only until federal immigration agents arrive and take that person into custody.”

Historically, the Texas Department of Public Safety personnel has worked well with the Border Patrol, said Gil Kerlikowske, commissioner of U.S. Customs and Border Protection from 2014 to 2017.

“They make traffic stops and also coordinate air surveillance,” Kerlikowske said. The role of the state public safety personnel and National Guard generally has been to observe and report or do administrative office work. That frees up Border Patrol agents, who are trained on how to interact with migrants, he said.

But Texas’ latest call on forces from faraway states is something different, he said.

“This is not only ‘political theater,’ it is actually dangerous for these officers,” Kerlikowske told PolitiFact. “The border environment and the culture of the border communities is something these (out of state) officers are not familiar with.”

Andrew Arthur, a fellow at the Center for Immigration Studies, which supports lower levels of immigration, disagreed with critics who dismiss the Abbott-Ducey effort as a photo opportunity for Republican governors.

He said officers from other states are not enforcing federal border laws in Texas, but are enforcing Texas state law at the border. That could include backing up Texas state troopers or highway patrol pulled off their duties to help with law enforcement along the border, he said.

“They are going to do real police work,” said Arthur.

Who will cover the costs?

In most cases, it will be taxpayers from the states funding the resources and personnel.

Seth W. Christensen, a spokesperson for the Texas Division of Emergency Management, told PolitiFact that “resources sent from other states are being sent at their expense.”

The law that established the compact among states provides for the requesting states to reimburse other states. Katie Strickland, a spokesperson for Gov. Ron DeSantis, said Florida plans to seek reimbursement from Texas, but its responding agencies “have sufficient resources to absorb the costs.”

In Arkansas, Hutchinson’s spokesperson said the cost is about $575,000 for 30 guard members for a 90-day deployment. Idaho has opted to cover its own costs, estimated at $53,391.

In South Dakota, the governor’s spokesperson would not detail the cost of the operation, citing “security reasons.” However, a wealthy Republican donor from Tennessee, Willis Johnson, offered $1 million to help cover the costs. Payment came through the nonprofit Willis and Reba Johnson’s Foundation and was received by the state Department of Public Safety.

The unusual private donation for a government function has raised some legal and ethical questions, while state officials have pointed to laws that they say allow such a donation.

Johnson, who regularly donates to Republicans running for Congress, made his fortune as the founder of Dallas-based Copart, a business that handles online auctions for used and damaged cars. He told PolitiFact that his nonprofit foundation provides money for Christian causes.

This article was originally published by PolitiFact, which is part of the Poynter Institute. It is republished here with permission. See the sources for these fact checks here and more of their fact checks here.