The head of the NYPD sergeants union said on Sunday that rank-and-file officers are eager to help the Trump administration deport undocumented immigrants, and feel stifled by declarations by the mayor and police commissioner in defense of the so-called sanctuary city policy.

Since November 2014, the NYPD has not directly assisted Immigration and Customs Enforcement officials except in cases of defendants accused of certain serious offenses. Following Donald Trump's election, and in light of Trump's campaign pledges to round up and deport many if not all of the estimated 11 million undocumented immigrants in the U.S., Mayor de Blasio vowed to do "everything we know how to do to resist that." An estimated 500,000 undocumented immigrants live in New York City.

Speaking to billionaire Gristedes owner John Catsimatidis on his AM 970 radio show, Sergeants Benevolent Association president Ed Mullins referenced a New York Post report that the city's immigration enforcement policy let an undocumented man and alleged MS-13 gang member briefly evade immigration agents because Rikers Island jailers did not notify the feds of his release following a disorderly conduct arrest.

"It's almost like the world is upside-down right now," Mullins said of the policy.

In a recent memo affirming the NYPD's policy of limited ICE cooperation, police Commissioner James O'Neill wrote, "It is critical that everyone who comes into contact with the NYPD, regardless of their immigration status, be able to identify themselves or seek assistance without hesitation, anxiety or fear."

Cops on the beat don't agree, according to Mullins:

Make no mistake about it, the members of law enforcement in the NYPD want to cooperate with ICE. I speak to cops every day. They want to cooperate with ICE, they want to work with fellow law enforcement agents...There is a point where there is a moral obligation, and as the chief law enforcement officer of the city, you yourself have to be able to follow the direction of law.

We don't get to participate in the laws that we want. If that's the case, then we're waiving all the federal laws for law enforcement officials—then they can go out and break the law. I mean, that's total lunacy that something like that could possibly happen.

Mullins said that there are "thousands and thousands of immigrants in New York City who are trying to live the American dream," but added that "people who are committing crimes, they don't belong in the country...in the case where you're illegal, why even spend the money to incarcerate them? Just send them back."

Current state and federal prison sentencing regimes typically require immigrants convicted of crimes to serve out prison sentences in American facilities before deportation. Trump has said he wants to send people found to have crossed the border illegally to Mexico while they await deportation hearings, but Mexico's Foreign Minister Luis Videgaray has said that there is no chance Mexico will accept that.

Trump's Attorney General Jeff Sessions has reinstated the federal Bureau of Prisons' use of private prisons months after the agency began ceasing their use following exposés of abuses, including in prisons where immigrant convicts were held—ICE never stopped using them for detainees held for immigration violations.

Former president Barack Obama oversaw the deportation of more than 2.7 million people, more than any other president. Midway through his second term, the Obama administration created a system for prioritizing deportations, putting the focus on felons and recent arrivals. Weeks into his presidency, Trump has ripped up Obama's Priority Enforcement Program and replaced it with an open-ended set of criteria that essentially gives ICE agents free rein in determining who to single out for deportation. Trump is also threatening to revoke federal funding from cities where police don't fully cooperate with immigration officials. It's not clear how he would accomplish this, and moves toward it would face legal hurdles, but federal cuts would most affect housing assistance and counter-terror programs.

In light of de Blasio's avowed opposition to Trump's policies, immigrant rights and police reform advocates have been pressing the mayor and NYPD to end the policy of so-called Broken Windows enforcement, which, they point out, imperils even legal immigrants swept up by police focused on low-level violations, and is carried out overwhelmingly against nonwhite offenders.

For example, the NYPD wrote summonses to 5,502 people and arrested 2,000 in January for fare evasion, prompting criticism from MTA board member David Jones, who said at the January meeting, "This is like Victor Hugo, Les Miserables, persecuting people for stealing bread."

Jones said that he would have been concerned about the figures pre-Trump, but, "Now it’s heightened. We just don’t want to give more ammunition and more reason to deport people who have engaged with us because of poverty."

NYPD Deputy Commissioner for Legal Affairs Lawrence Byrne told reporters in response to Jones's concerns that "Nobody is getting deported for a minor offense," saying that "Even if you're a recidivist and jumped a turnstile for the fourth or tenth time," it wouldn't trigger an ICE notification.

The latter piece of this is technically true: theft of services, a misdemeanor, is not on the NYPD's list of offenses that prompt direct information-sharing. However, police share the fingerprints of everyone they arrest with the FBI, which shares them with the Department of Homeland Security, meaning even if prosecutors drop charges against an immigrant, federal immigration authorities will find out about the bust. ICE agents are known to haunt New York's courthouses trawling for immigrants dealing with legal cases.

What's more, theft of services is categorized as a "crime of moral turpitude." Convictions for crimes that fall under this legal designation can mean deportation, not just for undocumented immigrants, but for visa and green card holders.