Masked immigration agents seizing a graduate student on a suburban street. Officers marching into campus housing and arresting another, ignoring his distraught wife as she asks where he is being taken. They have been among the defining images of President Trump’s second term.

But with Mahmoud Khalil’s release on bail from federal detention on Friday, the early phase of the Trump administration’s high-profile crackdown on international students who have spoken out in favor of Palestinian rights appears to have ended for now.

As a detention campaign — an attempt to confine the students while their deportation cases play out — Mr. Trump’s efforts appear to have been unsuccessful. In addition to Mr. Khalil, many of the other administration’s most prominent targets have been freed, while immigration agents have been barred from even trying to detain others.

Judges in those cases have sent an unequivocal message: The administration cannot detain people solely because of their speech.

“The unanimity of federal court decisions on this issue should send a clear message to the executive branch that it cannot snatch people off the streets for peacefully protesting and put them in prison indefinitely,” said Elora Mukherjee, director of the Immigrants’ Rights Clinic at Columbia Law School. “The federal courts have unequivocally protected the First Amendment rights of the noncitizen protesters in these cases, literally across the country.”

Mr. Trump’s second term has been rife with similar efforts to suppress disfavored speech, as the administration bars news outlets from the Oval Office and cancels federal grants on the basis of words that its officials dislike. And while many of those efforts have been legally unsuccessful, it is difficult to measure their broader political effect.