The nation’s chronically overburdened immigration courts are becoming even more crowded as a wave of illegal immigrants enters the system and fewer are able to exit it.

The 334 immigration judges working nationwide each juggle dockets of some 2,000 cases. The backlog has reached nearly 700,000, more than double what it was six years ago, and the average case is in court for more than two years.

This frustrates people on both sides of the immigration debate. Court hearings are scheduled for months or years into the future, delaying deportations for those who have no right to stay and putting off permission to remain for those who do.

The Trump administration has campaigned to increase arrests and deportations of illegal immigrants. The number of pending cases has increased nearly 150,000—a 26% jump—since Donald Trump took office. The monthly increases during the Trump administration exceed all but the last two months of the Obama administration.

“The winner is an alien who has a really lousy case, because they get to be here for years waiting for a case to come up,” says Judge Lawrence Burman, of Arlington, Va. His calendar is full through 2020, and he has scheduled hearings on the docket of a future judge who has not yet been hired. Immigration judges aren’t permitted to speak to the media; Mr. Burman spoke in his capacity as an official with the union representing immigration judges.