Judge Deborah Boardman, a Biden appointee, ruled that the order is likely unconstitutional. This marks the second time a federal court has blocked the policy. The nationwide injunction is slated to remain in place while the case is adjudicated.

Boardman said the civil rights group plaintiffs, five pregnant women whose children would not be granted citizenship under the order, were likely to succeed on the merits. The plaintiffs are represented by the CASA and the Asylum Seeker Advocacy Project.

Trump’s executive order seeks to deny U.S. citizenship to children born in the country unless at least one parent is a U.S. citizen or lawful permanent resident. The administration argues that children of undocumented immigrants and temporary visa holders are not “subject to the jurisdiction” of the United States, a reinterpretation of the 14th Amendment.

The ruling follows a temporary restraining order issued by Senior U.S. District Judge John Coughenour in Washington state on Jan. 23. Coughenour, a Reagan appointee, strongly rebuked the Trump administration’s legal rationale, calling the order “blatantly unconstitutional” and comparing it to a modern version of the Dred Scott decision. The judge also rejected the government’s argument that states lack standing to challenge the policy, emphasizing the 14th Amendment’s guarantee that “all persons born or naturalized in the United States” are citizens.

The lawsuits challenging the order involved plaintiffs including Democratic attorneys general from Washington, Oregon, Illinois, and Arizona, along with civil rights groups. Washington Attorney General Nick Brown argued the policy could strip citizenship from 150,000 newborns annually, including 4,000 in his state.

The legal battle is expected to reach the Supreme Court, as Trump has vowed to appeal all the way up to the justices if need be. Meanwhile, a group of 18 House Republicans, including Judiciary Committee Chairman Jim Jordan (R-OH) and Rep. Chip Roy (R-TX), have filed amicus briefs in federal courts supporting Trump’s executive order to end birthright citizenship.

John Yoo, a law professor at the University of California, Berkeley, said Tuesday that he believes Trump’s order goes against conventional and historical understandings of the 14th Amendment.

“I’ve read the theories for this. They are primarily people who are political theorists who are saying the American Revolution adopts this kind of Lockean social compact where we have citizenship by consent, and this is the American rule. But when you ask, well, how does that rule actually work? Do you see any evidence of any state adopting that rule? I don’t see any statutes that do that for citizenship,” Yoo said during a recent Federalist Society panel.

Amy Swearer, a senior legal fellow at the Heritage Foundation’s Edwin Meese III Center for Legal and Judicial Studies, cited during the panel influential scholars such as Henry Campbell Black, who argued that birthright citizenship only applied to those born to immigrants who were lawfully and permanently residing in the country.

However, both experts contended that it might be unlikely for the Supreme Court, under Chief Justice John Roberts’s leadership, to make any ruling that would subvert the long-standing precedent of birthright citizenship. Boardman, the Maryland federal judge who issued the injunction on Wednesday, also said she believes her order aligns with long-standing high court precedent.

The judge in Washington is set to hold a hearing Thursday on whether to extend his restraining order into a preliminary injunction, and it is unclear how Boardman’s decision may affect that hearing.