The Supreme Court on Friday allowed President Trump’s executive order restricting birthright citizenship to take effect in some parts of the country for now, ruling that several district court judges had exceeded their authority in blocking the policy across the country.

The court stressed that its ruling did not address the constitutionality of Mr. Trump’s order itself, which bars government agencies from automatically treating babies as citizens if they were born on domestic soil to undocumented migrants or foreign visitors without green cards.

Rather, it focused on so-called universal injunctions, a tool by which district courts could impose a nationwide freeze on executive branch policies that have faced legal challenges. Such injunctions applied broadly, extending to people who are not plaintiffs in the lawsuits challenging those actions. Those types of injunctions were once rare, but had become increasingly common in recent years.

The ruling was 6 to 3, split along ideological lines.

Here are some highlights.

The majority opinion, written by Justice Amy Coney Barrett, held that the Federal Judiciary Act of 1789, which created lower courts, does not give district court judges the power to issue preliminary injunctions granting relief to people other than the plaintiffs before them. The rest of the conservative wing — Chief Justice John G. Roberts Jr. and Justices Clarence Thomas, Samuel A. Alito Jr., Neil M. Gorsuch and Brett M. Kavanaugh — joined her opinion, which concluded:

The dissent was written by Justice Sonia Sotomayor, who summarized her argument from the bench, a rare step that signals profound disagreement. The opinion, joined by Justices Elena Kagan and Ketanji Brown Jackson, asserted that the majority’s ruling would allow the government to play games with constitutional rights:

In the majority opinion, however, Justice Barrett countered that nationwide relief could still be obtained through class-action lawsuits. Noting that there are limits on when judges can certify a class, which are found in Rule 23 of the Federal Rules of Civil Procedure, she added that universal injunctions had evolved into an improper workaround of such limits.