If landmark Supreme Court rulings sometimes come in unlikely cases, the justices’ consideration Monday of a law that gives 50,000 Americans born in Jerusalem the option of listing “Israel” as their birthplace seems to fit the bill.

In a little more than an hour, lawyers and the justices debated whether the president has sole authority to guide the nation’s foreign policy, whether Congress is an equal — or perhaps superior— partner and whether the Supreme Court even has a role to play in sorting it out.

The examination began with George Washington, included George W. Bush and his successor — who on this subject are united— and touched on the sensitive subject of Middle East relations.

The justices seemed to indicate in their questioning that the executive branch had the upper hand, although perhaps not to the extent that the Obama administration thinks.

“Our cases say repeatedly that the president is the sole instrument of the United States for the conduct of foreign policy,” Justice Antonin Scalia said at one point in the discourse.

“But it doesn’t necessarily mean that the president determines everything in foreign policy.”

The controversy is over a 2002 law passed by Congress regarding passports. It says that a U.S. citizen born in Jerusalem may request his or her birthplace to be listed as Israel. This was an attempt to nullify State Department instructions that only “Jerusalem” be listed, a recognition of the official U.S. policy of neutrality over national sovereignty of the holy city.

Bush said his administration would not carry out Congress’s dictate, which was contained in a spending bill and the Obama administration has adopted the same stance.

Nathan Lewin represents Ari and Naomi Zivotofsky, U.S. citizens whose son Menachem Binyamin was born in a west Jerusalem hospital in 2002 and who want the boy’s passport to say he was born in Israel.

Lewin attempted to present the law as a simple and legitimate exercise of Congress’s power to regulate passports.

“All that happens with this statute is that 50,000 American citizens have the same passport as 100,000 other American citizens who were born in Tel Aviv or Haifa,” Lewin said. “It just says ‘Israel.’ It doesn’t say ‘Jerusalem, Israel.’ ”

He didn’t get far. The title of the provision, Justice Samuel A. Alito Jr. pointed out, is “United States Policy With Respect to Jerusalem as the Capital of Israel.”

Justice Elena Kagan jumped in: “It’s a passport statute that seems to have nothing to do with the immigration functions that passport statutes usually serve. It seems to have everything to do with Congress’s declaration of a foreign policy.”

Justice Sonia Sotomayor asked, “What entitles Congress to trench on a presidential power that has been exercised virtually since the beginning of the country?”

Lewin replied that it was a shared responsibility, but Scalia said that if the president is required to follow the dictates of laws passed by Congress, that puts the legislative branch in a “superior” position.

But the justices seemed equally suspicious of Solicitor General Donald B. Verrilli Jr.’s claim that presidents since Washington have exercised the sole authority given to them in the Constitution to recognize foreign governments.

That “textual commitment,” Verrilli told the court, resides in the document’s determination that the president alone may “receive Ambassadors and other public Ministers.”

Some justices wondered whether that was not a slim reed. But Verrilli, under questioning from Kagan, said the administration would be making the same argument even without a specific command in the Constitution.

When George Washington faced a decision whether to recognize the revolutionary government of France, Verrilli said, he “consulted with his cabinet, and of course his cabinet included Jefferson and Madison and Hamilton and Jay.” The conclusion was that “they didn’t even need to send a message to the Congress” of the recognition decision, Verrilli said.

A lower court tossed the Zivotofsky case by saying it was a “political question” between the executive and legislative branches beyond the authority of the courts. The justices did not seem inclined to agree with that.

Several said that if they decided, for example, that the executive branch alone has the recognition power and thus the courts had no role, that would not be far from deciding the merits of the case.

There was a moment of levity in the serious discussion. Kagan told Lewin he might have a better case if Congress had been neutral, saying those born in Jerusalem could choose either Israel or Palestine.

Lewin replied Palestine was an option for those born before 1948, when Israel became a state.

“Well, you have to be very old to say Palestine,” said Kagan, who at 51 is the youngest justice.

“Not all that old,” said Justice Ruth Bader Ginsburg, who at 78 is the oldest.

The case is Zivotofsky v. Clinton .