The Biden administration has officially reinstated its enforcement guidelines for U.S. Immigration and Customs Enforcement (ICE). The move comes after the Supreme Court reaffirmed the federal government’s authority to set priorities in immigration enforcement – and to discourage federal agents from spending time and energy on noncitizens who aren’t priorities.

This includes not just the guidance issued to ICE’s division of Enforcement and Removal Operations (ERO), which arrests and detains people inside the United States, but to its Office of the Principal Legal Advisor (OPLA) – the office for prosecutors in immigration court. (Prosecutors, unlike immigration judges and court staff, are ICE employees under OPLA and not the Department of Justice.)

The administration’s enforcement priorities are based on a Department of Homeland Security-wide memo sent by Secretary Alejandro Mayorkas in September 2021. The memo set out three broad categories of enforcement priorities: threats to national security (i.e., terrorism concerns); threats to public safety (defined in part by criminal history); and threats to border security (including anyone who entered the U.S. without authorization after November 1, 2020).

For prosecutors, adhering to the guidelines can be tricky, since they can not only bring new deportation cases against immigrants (or decline to do so) but to stop cases that are already proceeding.

The Mayorkas memo didn’t specify exactly what agencies should do about people who didn’t fall into those categories. OPLA had received preliminary guidance in summer 2021, but offices around the country didn’t properly implement it. It took until April 2022 for Chief Counsel Kerry Doyle to issue final implementation guidance to OPLA – which was only in effect for a few months before a federal judge ruled that the enforcement priorities were unlawful in June 2022. At that time, the federal government stopped applying the Mayorkas memo, as well as the sections of the Doyle memo that relied on it.

Now, with the judge’s order overturned by the Supreme Court (which ruled that the Republican-led states challenging the priorities didn’t have the power to bring the lawsuit to begin with), both memos are again in effect.

The reality of enforcement policy, though, is murkier than the on-off switch that federal litigation makes it sound like. Government agents have inherent discretion to decide how to focus their resources. The questions are what level the priorities are being set (on a spectrum from agents on the ground being allowed to do whatever they want, to headquarters dictating how they spend their time); how formally they’re articulated; and whether the public is given any information about how (and whether) the priorities are being followed.

The fuzziness of enforcement priorities works both ways. Even when the Mayorkas and Doyle memos weren’t in effect, ICE – both ERO and OPLA – still had discretion about who to target for enforcement, and what to do with the 2.4 million cases already in the pipeline. It also means that even when they are in effect, ICE employees aren’t prevented from ignoring the guidelines or reinterpreting them.

The government doesn’t proactively share information about its implementation of the priorities. But through the efforts of the American Immigration Council and other organizations that use the Freedom of Information Act to get insight into how the government works, we have some clues.

For ERO enforcement actions – including arrests and removals – a resource recently compiled by the Council and the Immigrant Legal Resource Center shows that ICE agents routinely arrested and deported noncitizens who didn’t fit into any of the three specified priority categories, instead creating a shadow fourth category called “Other Priority.”

From February 18 to November 11, 2021, over a third of enforcement actions – 35.6% – were designated as “other priority.” The report is a useful reminder that having written national enforcement priorities in theory isn’t sufficient to ensure that ICE is adhering to those priorities – and suggests that, in large part, it hasn’t.

We don’t have similarly explicit data on OPLA’s implementation of enforcement priorities – i.e., their effect on outcomes in immigration court, rather than arrests and deportations. And because the Doyle memo was only in effect for one full calendar month, it’s hard to see a clear distinction between before, during, and after. But the Transactional Records Access Clearinghouse (TRAC)’s database of immigration court outcomes gives a little visibility.

When it comes to a prosecutor’s choice to open a case against a noncitizen to begin with, the TRAC data strongly suggests that the OPLA priorities memo doesn’t constitute a massive change. In 2022 and 2023, over three-quarters of newly-filed deportation cases are against people who have been in the U.S. less than one year – who would, presumably, fit under the “border security” enforcement priority. The volume of new cases coming from the border is a substantial cause of the immigration court backlog – one that the administration’s crackdown on asylum seekers after the end of the Title 42 public-health order has, apparently, done little to alleviate. As long as people are considered enforcement priorities simply based on when they entered, the impact of prosecutorial discretion on new cases will be limited.

When it comes to how a case is resolved, however, the data tells a different story.

When a case has already begun and a formal Notice to Appear has already been entered into the record, the Doyle memo encourages prosecutors to exercise favorable discretion (where they think it’s merited) by asking judges to terminate the case – permanently removing it from the docket. And in spring of 2022, with the advent of the Doyle memo, terminations soared. In May 2022, over 27,000 cases were terminated – compared to only 10,000 removal orders issued that month by judges.

Termination levels dropped in summer and fall – though they were still happening more often than under prior administrations. Earlier this year, though, terminations began rising again, even before the Doyle memo was fully reinstated.  In June 2023, the last month for which TRAC data is available, about as many cases ended with termination as removal orders – about 18,000 apiece.

It’s important to note that these outcomes aren’t always what immigrants and their lawyers (if they have them) want – terminating a case, for example, means someone is denied a chance at relief from an immigration judge and can lose their U.S. work permit. Even if the outcomes urged by the Biden administration aren’t exactly what advocates want, it’s still important to know whether and how their guidance is actually being followed.

Without that, there’s no way to hold the government accountable for its own promises about how it’s exercising its power. Having public and explicit guidance, like the Doyle memo, is important. But we know it doesn’t truly dictate policy reality. And the onus remains on the government to demonstrate that this time, the enforcement priorities aren’t being undermined or ignored.