A crucial piece of President Donald Trump’s deportation machine is not working the way he wants. He’s arresting thousands more undocumented immigrants than his predecessor, and illegal border traffic has dropped to historically low levels.

Still, something is wrong.

“We have to bring them before a ridiculous court system,” Trump complained at the White House earlier this month.

The vast, complicated immigration court system is designed to uphold a foreigner’s right to due process in the United States before he can be deported. That includes everyone from longtime residents who once overstayed a visa to an asylum-seeking Central American child who arrived alone at the border just days ago.

Trump’s displeasure lies with the system’s massive list of unclosed cases. The courts, overseen by the Justice Department’s Executive Office for Immigration Review, or EOIR, face a backlog that’s grown to nearly 685,000 cases over the last decade. It takes an average of 561 days for a case to be closed.

The backlog is stymieing Trump. Many of the immigrants he wants to remove — including asylum-seeking mothers and children like those in the caravans he’s criticized on Twitter — cannot be sent home until they’ve had a day in court. Asylum cases, in particular, can take more than a year to adjudicate.

Watch: How the Senate Immigration Debate Stalled

Lawmakers have long sought an effective means of tackling the backup without threatening an individual’s constitutional right to due process. Under Trump, the Justice Department is adding more judges — something Republicans and Democrats both support — but it is also imposing strict performance requirements, drawing the ire of advocates and judges alike.

Judges say there’s little chance the new performance standards — completing at least 700 cases a year with an appeals rate of under 15 percent, for starters — will have the impact Trump desires.

“Instead of reducing the backlog, it will increase the backlog,” said Ashley Tabaddor, president of the National Association of Immigration Judges.

The administration says the requirements are more than reasonable. Attorney General Jeff Sessions said completing 700 cases a year is “about average” for an immigration judge.

“This is not a radical goal, but a rational policy to ensure consistency, accountability, and efficiency to our immigration court system,” Sessions told a coalition of border sheriffs in New Mexico on Wednesday.

Tabbador said the requirements would leave a judge little time to dispatch a case.

“That means that asylum cases that often have hundreds of pages of supporting documents, hours of testimony, deliberation, the time to make a decision … all of that is allotted about two-and-a-half hours,” she said. “Clearly, this is not justice.”

Challenges old and new

The backlog at immigration courts has steadily increased every year since 2008, including by more than 100,000 cases from fiscal 2016 to fiscal 2017, according to Syracuse University’s Transactional Records Access Clearinghouse, known as TRAC.

Previous administrations have tried their own ways of reducing it, with little success. John Ashcroft, former President George W. Bush’s first attorney general, streamlined the appeals process following the 9/11 terrorist attacks, but the move was seen as exacerbating the problem further.

Under President Barack Obama, EOIR established what critics called a “rocket docket” focused on cases involving unaccompanied child migrants, who flooded the system with asylum claims after they arrived at the border by the tens of thousands starting in 2014. Again, the backlog continued to swell.

Trump tried a handful of strategies before imposing case completion quotas on judges, including streamlining the hiring process and trying to limit the number of times a judge could delay a decision on a case. Sessions even sent judges to the border, and is expanding a program for holding hearings by video teleconference.

Congress has done its part, too, by approving funding in fiscal 2018 for up to 449 immigration judges — a 35 percent increase over current levels, according to a DOJ spokesman. Because of a lengthy hiring process, only 334 judges are hearing cases right now, but a plan Sessions announced earlier this month has reduced that time by more than half, the spokesman said.

Still, none of Trump’s initiatives so far have reduced the backlog. Sessions told Congress late last year that it would begin to shrink by January. Instead, it’s grown by roughly 50,000 cases since fiscal 2017, according to TRAC.

One reason, officials say, is there are simply not enough judges. James McHenry, the director of EOIR, told lawmakers last November that it would take about 700 judges to reverse the decade-long buildup.

Another reason the backlog keeps growing, critics say, is that the Homeland Security Department is arresting more people than the courts can handle. From Trump’s inauguration through the end of fiscal 2017, immigration agents made 110,568 arrests, a 42 percent increase over the same period the year before.

Meanwhile, EOIR closed just more than 204,000 cases, slightly fewer than the year before. TRAC projects a similar falloff in fiscal 2018, to about 200,000 closed cases.

“If you added to your police department by a hundredfold and didn’t add any judges or prosecutors, there’d be a problem,” said Rep. Zoe Lofgren of California, a former immigration lawyer and the ranking member of the House Judiciary Immigration and Border Security Subcommittee. “It’s the same thing.”

Due process

Defendants in immigration proceedings — even children and the disabled — are not guaranteed representation as they would be in criminal courts. Immigrant advocates are concerned about how the new requirements will affect children, many of whom don’t have an attorney and can’t speak English.

Given Trump’s agenda and his anti-immigrant rhetoric, children in immigration courts are more at risk than ever, advocates say.

“It’s not about identifying those who need protection and those who can be sent home,” said Wendy Young, president of the nonprofit organization Kids in Need of Defense, which represents asylum-seeking minors. “It’s about turning the case around and sending the person back. They’re turning protection systems on their heads.”

Young says placing a time limit on a child’s day in court could mean they don’t get a fair shot at pleading their case.

“It takes a long time to get the child to fully open up and explain why they might be here and what basis they may have for protection,” she said.

Advocates are equally concerned by DOJ’s announcement this month that it would temporarily halt a program that provides free legal advice to detained immigrants. They protested, saying the program was proven to save time during immigration proceedings.

Trump’s critics say that once judges feel the full effects of his new policies, they could be forced into rebellion.

“My guess is that judges will not comply if they can’t,” Lofgren said. “They want to be good employees — and most of them could make more money in the private sector — but they’re there to do justice.”