The Trump administration’s biggest obstacle to scaling up deportations of unauthorized immigrants is the massive backlog in immigration courts: Almost 700,000 immigrants are waiting to have their cases decided before the government can deport them.

Attorney General Jeff Sessions says he wants to fix the court backlog, but he’s just issued a policy that could add to it. Sessions opened the door to potentially reopening 350,000 deportation cases the government previously agreed to close.

Sessions’s decision was issued in the form of a ruling on an individual immigration court case, one that the Board of Immigration Appeals (the semi-appellate body for immigration court) had already ordered the judge to reopen.

But Sessions referred the case to himself for further review — something he’s done with increasing frequency over the past several months — and issued a broad ruling that goes beyond the fate of the one immigrant involved in the case: a decree that immigration judges don’t have the authority to remove cases from the docket, even when government prosecutors are the ones asking to close the case.

Sessions’s use of “self-referrals” has raised alarms among immigration lawyers and judges. One of their biggest concerns is that at the same time that Sessions is telling immigration judges to plow through the backlog, he’s forcing them to hear more cases — making it impossible for them to give each case the time they feel it deserves.

His new ruling seems to confirm that fear. While it won’t automatically add hundreds of thousands of cases to the already overloaded dockets of immigration judges, Sessions’s ruling makes it clear that he expects the Trump administration to start asking for immigrants to get hauled back into court.

Obama used immigration case closures like plea bargains. Under Trump and Sessions, that bargain is being broken.

The immigration court backlog has been a problem for years.

Most immigrants who are apprehended in the US without papers have a right to a hearing in immigration court to determine whether they can be deported and whether they qualify for some form of legal status or other relief from deportation. The same process exists for people who are caught crossing into the US but who claim to be eligible for some sort of relief, like asylum, and pass an initial screening. In both cases, only after the judge issues a final order of removal can the immigrant be deported.

But as the Department of Homeland Security (and specifically Immigration and Customs Enforcement) got resources to arrest more and more immigrants, the Department of Justice — under which immigration courts are housed — didn’t get enough to keep pace. With more and more people coming into the system and not enough increase in capacity to deal with them, the backlog ballooned.

The Obama administration tried to reduce the court backlog as part of its broader strategy of prosecutorial discretion, spending ICE’s resources on pursuing and deporting immigrants with criminal records, rather than longtime residents without prior contact with law enforcement. They did this by having prosecutors request that a case be closed; the judge wouldn’t rule on it but would just take it off the docket.

According to legal advocates, prosecutors often pushed to close cases in which the immigrant had a good chance of being found eligible for some sort of relief from deportation like asylum. Immigrants had a choice: They could allow their case to get closed — they wouldn’t get legal status, but they wouldn’t be ordered deported either — or they could keep fighting to get official relief, but the prosecution would fight them every step of the way.

Hundreds of thousands of immigrants took the first option. As of September 2018, there were more than 350,000 cases that had been closed and never reopened.

Sessions just ruled that the whole process was illegal.

His ruling claims that judges are only allowed to close cases when federal regulations explicitly mandate it, which is very infrequent. The rest of the time, once a case is on a judge’s docket, the judge is obligated to make a decision.

Closed cases won’t be reopened automatically; ICE will have to make a motion in individual cases it wants to put back on the docket. Sessions’s ruling acknowledges that adding all 350,000 cases at once would make the backlog impossible to manage. But his wording seems to imply that it’s not a matter of if a given case will be reopened, but when: “I expect the recalendaring process will proceed in a measured but deliberate fashion that will ensure that cases ripe for resolution are swiftly returned to active dockets,” the ruling says.

Immigration advocates are concerned with the ruling for two reasons. For one, they feel that Sessions is targeting immigrants who “played by the rules” — who agreed to forgo a chance to seek legal status because the Obama administration wanted to close their cases and now are being punished by the Trump administration for going along with it.

“Many immigrants who had claims for immigration relief relied on government assurances that they wouldn’t be deported if they agreed to let their cases be closed,” said Jeanne Atkinson, the director of the Catholic Legal Immigration Network, in a press statement. “Now, years later, the Trump administration is changing the rules on immigrants who did exactly what the government instructed them to do.”

But they are more fundamentally concerned with the functioning of immigration court itself.

Sessions is pressuring immigration court judges to move through cases more quickly. But he’s just taken away the tool they’ve used in the past to get a case off their plate. Judges will be less able to allow an immigrant extra time to put together a case or to even seek an attorney at all. The more pressure is put on immigration judges from above, and the more Sessions moves to block their safety valves, the less likely judges are to give immigrants a chance to fully make their cases before banging the gavel on their deportations.