Civil rights groups and immigration advocates slammed the Trump administration after it filed a series of lawsuits and issued measures against state and local governments that have enacted "sanctuary" policies.

The latest announcement came on Monday when US Attorney General William Barr said the Justice Department was suing the state of New Jersey and King County, Washington, over immigration policies that offer protections to undocumented immigrants.

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"When we are talking about sanctuary cities, we are talking about policies that are designed to allow criminal aliens to escape," Barr said in a statement.

"These policies are not about people who came to our country illegally but have otherwise been peaceful and productive members of society. Their express purpose is to shelter aliens whom local law enforcement has already arrested for other crimes. This is neither lawful nor sensible," he added.

But rights groups say sanctuary policies protect immigrants' rights and make communities safer. They also say President Donald Trump's retaliatory moves are legally problematic and aimed at appealing to his conservative base.

Attorney General William Barr waving after speaking at the National Sheriffs' Association Winter Legislative and Technology Conference in Washington, DC [Susan Walsh/AP Photo]

"This is just the latest chapter in a long story of DOJ (Department of Justice) failures. The Department of Justice has already lost repeatedly in its efforts to punish states and cities for exercising choices that the Constitution guarantees them," Omar Jadwat, director of the American Civil Liberties Union's Immigrants' Rights Project told Al Jazeera in an emailed statement.

"States and cities have declined to act as ICE's (Immigration and Customs Enforcement) henchmen, deciding instead to make their whole communities safer," Jadwat said.

Grace Meng, a senior immigration researcher for Human Rights Watch said the Trump administration's move will only exacerbate an already existing atmosphere of fear among immigrant communities, stoked through the president's rhetoric and previous policies.

"The basic premise of the Trump administration is his xenophobic take on immigrants, foreigners, and his efforts to argue that any problems that society is facing has been brought from the outside, rather than addressing that there are really complex causes that need to be addressed in a meaningful way," Meng said.

'Safe place to live together'

Hundreds of jurisdictions at the state, county and city level have enacted laws and regulations that offer some protections to undocumented migrants or limit cooperation between local law enforcement federal officials.

New Jersey prohibits state and local law enforcement from sharing information about undocumented inmates. Washington State's King County prohibits the Department of Homeland Security (DHS) from using its international airport for deportation flights. New York passed a law that allows undocumented migrants to apply for driver's licenses and limits federal immigration authorities from accessing motor vehicle records.

Protesters holding up signs outside a court in San Francisco after a federal appeals court gave the Trump administration a rare legal win in its efforts to crack down on sanctuary cities [File: Haven Daley/ AP Photo]

Meng said while sanctuary policies vary across cities and states, they are premised on the idea that we "cannot separate out immigrants in the community" and the rationale that undocumented migrants are threatening public safety is "completely false."

"It comes from a recognition that the community cannot be safe unless immigrants in the community, both documented and undocumented feel comfortable going to the police when they witness a crime or are victims of a crime," Meng told Al Jazeera. "All of us are in this effort to create a safe place to live together."

Observers say Trump, who has made a crackdown on immigration a centrepiece of his presidency, has been trying to retaliate against sanctuary cities since he took office and his administration's latest moves signal to his base in advance of the November 3 election that he will continue to be tough on the issue.

In his State of the Union Address earlier this month, Trump railed against sanctuary cities, falsely claiming these jurisdictions "order police to release dangerous criminal aliens to prey upon the public, instead of handing them over to ICE to be safely removed."

Data shows that cities and towns with sanctuary policies do not have higher crime rates compared with non-sanctuary jurisdictions, according to the Center for American Progress, a liberal think-tank.

US President Donald Trump listening during a round table meeting with members of law enforcement about sanctuary cities in the White House in Washington, US [File: Leah Millis/Reuters]

Despite other research with similar findings, Trump often cites individual cases in which an undocumented immigrant commits a crime as justification for the administration's measures.

Alex Nowrasteh, director of immigration studies at the Cato Institute's Center for Global Liberty and Prosperity, said the Trump administration has been contributing to the spreading of misinformation regarding sanctuary laws.

"It's not a get out of jail free card," Nowrasteh told Al Jazeera.

"When undocumented migrants commit crimes, they are still going to be turned over to ICE and deported," he said.

Nowrasteh added that Trump's efforts have little chance of succeeding in the courts, where past measures have been blocked.

"Legally, it's going to be difficult for the Trump administration to prevail on this, but it's going to make the cities, localities and states fight hard to keep their policy," Nowrasteh said.

Matthew Albence, right, acting director of US Immigration and Customs Enforcement, speaking during a news conference blaming the 'sanctuary policies' of New York City for the sexual assault and killing of a 92-year-old woman [Jim Mustian/AP Photo]

New York sued the Trump administration this week over a rule that blocks hundreds of thousands of residents from enrolling in federal programmes that help cut down on airport security wait times.

In issuing the rule, the administration cited the state's so-called "Green Light" law that allows for undocumented individuals to apply for driver's licences.

The state called the ban a "punitive measure intended to coerce New York into changing its policies".

Officials in the state of New Jersey were equally defiant after Barr's announcement on Monday.

"Once again, the Trump Administration is sacrificing public safety for political expedience," New Jersey Attorney General Gurbir Grewal said in a statement.

"Thankfully, nothing about today's lawsuit changes our work on the ground," he added. "While the President grandstands, we're focused on protecting the nine million residents of New Jersey."