The Supreme Court ruled on Thursday that the Trump administration may not immediately proceed with its plan to end a programme protecting about 700,000 young immigrants known as Dreamers from deportation, dealing a surprising setback to one of President Trump’s central campaign promises.

Chief Justice John G. Roberts Jr wrote the majority opinion, joined by the court’s four more liberal members in upholding the executive action by President Barack Obama that established the programme, Deferred Action for Childhood Arrivals, or DACA. But the chief justice made clear that the decision was based on procedural issues and that the Trump administration could try to redress them.

“We do not decide whether DACA or its rescission are sound policies,” the chief justice wrote. “We address only whether the agency complied with the procedural requirement that it provide a reasoned explanation for its action.”

Still, the decision was the second this week in which the court reached a result in a major case that elated liberals. On Monday, it ruled that LGBT workers were protected by a landmark civil rights law. Chief Justice Roberts was in the majority in that decision, too.

Trump responded with an angry attack on the court.

“These horrible & politically charged decisions coming out of the Supreme Court are shotgun blasts into the face of people that are proud to call themselves Republicans or Conservatives,” he wrote on Twitter. And he made clear that he would make the composition of the court a campaign issue, as he did in 2016.

The court’s decision was provisional, and it did not remove the uncertainty that young immigrants have lived with — including the possibility of being forcibly returned to countries many of them cannot even remember — since they arrived in the US as children. The DACA programme itself provided only a renewable two-year deferral of possible deportation, with no pathway to citizenship.

“Today’s decision allows Dreamers to breathe a temporary sigh of relief,” said Stephen Yale-Loehr, a law professor at Cornell.

But young immigrants said they were surprised and delighted that the court had ruled in their favour.

“I’m actually still shaking,” said Joana Cabrera, who came to the US from the Philippines at age 9, and at 24 is on a team researching the use of robots in coronavirus testing in San Francisco. “I’m unbelievably happy because I was expecting the worst.”

Trump announced in September 2017 that he would wind down the programme, basing his decision on the argument that creating or maintaining it was beyond the legal power of any President.