A constitutional controversy that has agitated the nation from time to time for well over a century will be examined anew by the Supreme Court in a review that, in the end, might sweep broadly or it might leave much still undecided.

In an order Thursday afternoon, the Court set a special hearing for next month on three combined appeals by the Trump Administration, part of its attempt to deny U.S. citizenship to potentially thousands of children born here to foreign parents who are in the country illegally or only temporarily.

The Constitution’s 14th Amendment, ratified in 1868, has a clause that appears to guarantee U.S. citizenship to any child born anywhere that the nation’s federal government has “jurisdiction” – that is, anywhere it has the power to govern. The clause was added to the Constitution to assure citizenship to the children born to freed African slaves, thus overturning the Supreme Court’s infamous 1857 decision in Dred Scott v. Sandford that black people could not become citizens.

While the Supreme Court as long ago as 1898 gave a generous reading to that mandate of “birthright citizenship,” the Court has never settled how it would apply to children born to foreign parents who are in the U.S. without legal permission or are here legally but temporarily as students, workers or tourists. (The clause does not apply to children born to foreign diplomats serving here temporarily.)

An order issued by President Trump on the first day of his second term, in January, would bar all children born to parents here legally or temporarily from becoming American citizens. The order has been widely challenged in federal courts across the nation, and every decision so far has gone against that order. While all of those decisions are only temporary, all are now in force and thus forbid enforcement of the Trump order across the whole country.

In Thursday’s order, the Court said it was postponing, until the hearing now set for May 15, the Administration’s request to block the nationwide impact of the judges’ actions while lower courts continue to review the Trump order. According to Administration lawyers, no single District Court judge, in any state, should be allowed to dictate what happens with the Trump citizenship ban everywhere in the U.S. At most, those lawyers contend, a judge’s order should apply only to those who filed the legal challenges and the states where the judge sits.

That request has been resisted by the challengers, who argue that the Trump ban is so clearly unconstitutional that it should not go into effect anywhere, and that challengers should not have to sue, one at a time, maybe in scores of separate and widely dispersed courts, to contest the order’s constitutionality.

Since the Administration technically is not asking the Justices to decide whether Trump’s order is valid, the Court may not be planning to go beyond the test of individual judge’s authority. That, of course, is a vital procedural question that has arisen repeatedly as more and more individual judges are expanding the reach of their orders beyond those who sued.

But looming in the background of the Trump appeals is, indeed, the fundamental question of whether Trump had the authority to issue such an order at all. The Administration’s lawyers argue fervently that the President not only has the power but the constitutional duty to “protect the meaning and value of American citizenship” and thus deny it to illegal or legal visitors with no real ties to this nation.

There was nothing in Thursday’s order to even imply that the Court wants to confront that core issue now. However, if as few as four Justices among the nine want to reach that question, they have the power to push it to the fore, although it would take the votes of five to decide it in a final way. The order said nothing about adding that core question to the mix; sometimes, the Court does enlarge the questions it plans to answer, but it usually does so by telling the lawyers involved to discuss it when they file their written legal briefs.

The Court set the hearing on May 15 for just one hour, but the process the Court now uses in its public hearings usually runs longer than the set time, especially if the case is complex or far-reaching, as this one potentially is.

While President Trump’s January 20 order set in motion the controversy now before the Justices, the issue of the meaning of the Citizenship Clause has been a divisive one for generations.

And, over the past decade or more, conservative policy and legal activists and academics have been debating whether the Clause reaches every child born here to a foreign parent.

That debate focuses on whether the Clause applies only to those “subject to the jurisdiction” of the U.S. government, and that phrase means that the parents have some “allegiance” to the government or plan to remain here permanently. That debate at times has overtones of racism or of intolerance of people who are “different.”

There have long been proposals in Congress to narrow the sweep of the Clause by passing new legislation, but none of those has advanced on Capitol Hill. The Library of Congress’ Congressional Research Service has studied such proposals and concluded that “the weight of current legal authority suggests” that that approach would violate the Citizenship Clause.

Since none of those legislative measures has passed, they probably will not be an issue in the Supreme Court’s review.