The Supreme Court is meeting in private Friday with a key issue on its agenda — President Donald Trump ’s birthright citizenship order declaring that children born to parents who are in the United States illegally or temporarily are not American citizens.

The justices could say as soon as Monday whether they will hear Trump’s appeal of lower court rulings that have uniformly struck down the citizenship restrictions. They have not taken effect anywhere in the United States.

If the court steps in now, the case would be argued in the spring, with a definitive ruling expected by early summer.

The birthright citizenship order, which Trump signed on the first day of his second term in the White House, is part of his administration’s broad immigration crackdown. Other actions include immigration enforcement surges in several cities and the first peacetime invocation of the 18th century Alien Enemies Act.

The administration is facing multiple court challenges, and the high court has sent mixed signals in emergency orders it has issued. The justices effectively stopped the use of the Alien Enemies Act to rapidly deport alleged Venezuelan gang members without court hearings, while they allowed the resumption of sweeping immigration stops in the Los Angeles area after a lower court blocked the practice of stopping people solely based on their race, language, job or location.

The justices also are weighing the administration’s emergency appeal to be allowed to deploy National Guard troops in the Chicago area for immigration enforcement actions. A lower court has indefinitely prevented the deployment.

Birthright citizenship is the first Trump immigration-related policy to reach the court for a final ruling. Trump’s order would upend more than 125 years of understanding that the Constitution’s 14th Amendment confers citizenship on everyone born on American soil, with narrow exceptions for the children of foreign diplomats and those born to a foreign occupying force.

In a series of decisions, lower courts have struck down the executive order as unconstitutional, or likely so, even after a Supreme Court ruling in late June that limited judges’ use of nationwide injunctions.

While the Supreme Court curbed the use of nationwide injunctions, it did not rule out other court orders that could have nationwide effects, including in class-action lawsuits and those brought by states. The justices did not decide at that time whether the underlying citizenship order is constitutional.

But every lower court that has looked at the issue has concluded that Trump’s order violates or most likely violates the 14th Amendment, which was intended to ensure that Black people, including former slaves, had citizenship.

The administration is appealing two cases.

The U.S. Court of Appeals for the 9th Circuit in San Francisco ruled in July that a group of states that sued over the order needed a nationwide injunction to prevent the problems that would be caused by birthright citizenship being in effect in some states and not others.