A federal judge on Friday ordered the Trump administration to fully restore the Deferred Action for Childhood Arrivals program, giving undocumented immigrants who arrived in the U.S. as children a chance to petition for protection from deportation.

Why it matters: DACA was implemented under former President Obama, but President Trump has sought to undo the program since taking office. Friday’s ruling will require Department of Homeland Security officers to begin accepting applications starting Monday and guarantee that work permits are valid for two years.

The big picture: Roughly 640,000 immigrants are enrolled in the DACA program. The Trump administration has argued that the Obama-era program was an overreach of executive power.

• Multiple courts have prevented the Trump administration from ending the program in its entirety, before the Supreme Court ruled in June that the Trump administration violated federal administrative law in its attempt to terminate the program.
• In July, Acting DHS Secretary Chad Wolf closed the program to new applicants and shortened the period of work permits and protections from two years to one.
• U.S. District Court Judge Nicholas Garaufis, who handed down Friday’s decision, previously ruled that Wolf’s appointment violated the Homeland Security Act of 2002, concluding that Wolf had no legal authority to implement his July mandates.
• The Government Availability Office also found Wolf’s appointment invalid.
• Immigration advocates anticipated that President-elect Joe Biden would use executive action to bolster DACA even as the courts consider its validity.

But, but, but: Immigrants often referred to as “'dreamers' are not necessarily in the clear," the Washington Post notes.

• Attorneys general in multiple states have asked a federal judge to rule that DACA is unlawful.

What they’re saying: "Today's ruling opens the door for more than 1 million immigrant youth who have been unfairly denied their chance to apply for DACA and secure their future in this country," Karen Tumlin, one of the lawyers representing DACA recipients and applicants, told CBS News. "Our brave plaintiffs have said from the beginning of this lawsuit that their home is here, and the court rightly recognized that today."

• "The court reserves the right to impose further remedies if they become necessary," Garaufis wrote in his decision.