In August 1895, a young cook named Wong Kim Ark was about to disembark from the SS Coptic, after a long journey home to San Francisco from China, when U.S. customs officials denied him reentry.

He was not a U.S. citizen, they said. Never mind that Wong had been born in San Francisco’s Chinatown, not far from the port where he was now being held. The 14th Amendment’s provision for automatic citizenship for all people born on U.S. soil did not apply to him, officials later argued, because he and his parents were not “subject to the jurisdiction” of the U.S. at the time he was born.

Rather than back down, Wong took his case to the courts — and won.

In Wong’s case, the Supreme Court affirmed the constitutional guarantee of automatic citizenship for nearly all children born in the United States, a right that has deep roots in common law. Since that 1898 ruling, that expansive understanding of birthright citizenship has been the law of the land.

Now, the Trump administration wants to roll back the Wong Kim Ark ruling — and birthright citizenship more broadly — as it moves to crack down on immigration.

On his first day back in office, President Donald Trump signed an executive order declaring that the government would stop treating U.S.-born children of parents who are in the country illegally or are in the country temporarily as U.S. citizens.

The order prompted a flurry of lawsuits, mostly from Democratic attorneys general and civil rights groups. Last week, the order was indefinitely blocked. One federal judge called it “blatantly unconstitutional.” The Justice Department has already appealed one of the injunctions.

The Trump administration is pushing forward a reinterpretation of the 1898 decision, drawing on ideas from a small group of legal scholars like John Eastman, a lawyer known for drafting a plan to block congressional certification of the 2020 presidential election.

It is not clear that the Supreme Court, even with its conservative majority, would be inclined to take up such a case. Still, the recent moves may lay the groundwork for a protracted legal battle that critics of birthright citizenship hope will chip away at the long-standing precedent.

The Wong Kim Ark case “is settled law, or at least it’s as settled anything possibly could be,” said Amanda Frost, a law professor at the University of Virginia and an expert on immigration and citizenship law. “But that doesn’t mean it can’t get unsettled.”

Wong’s case arose during a similar moment of heightened national anxiety around immigration.

His parents were part of a wave of Chinese laborers who flocked to the United States starting in the mid-1800s in search of economic opportunities. Wong’s father ran a grocery store in San Francisco’s Chinatown neighborhood, and in an apartment above that store, his son Kim Ark was born in 1870.

The growing numbers of Chinese workers on the West Coast soon gave rise to economic competition and virulent racism. Vigilante mobs regularly terrorized and at times even lynched these immigrants, who were often portrayed as unassimilable, inferior and disease-ridden.

Federal laws reflected that bias as well, like the Chinese Exclusion Act of 1882, which barred most Chinese people from entering the country and banned them all from becoming naturalized citizens.

Around that time, Wong’s parents went back to China, taking their son with them. Lured by the promise of higher wages, though, Wong soon returned to the United States.

He was able to do so, despite the Chinese Exclusion Act, because lawmakers had adopted the 14th Amendment in 1868, two years before his birth. It states that “all persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

The amendment overruled the 1857 Dred Scott decision, which declared that African people who were enslaved in the U.S., and their descendants, were not American citizens.

For Wong and his supporters, the amendment’s broad language — especially the phrase “all persons” — meant that U.S.-born people like Wong were citizens, despite the Chinese exclusion laws. And the first few times he traveled, he was able to reenter the United States by proving that he was born in San Francisco.

But the government, seeking to close what they saw as a loophole, set out to find a test case, and landed on Wong.

The government’s lawyers seized on another phrase in the amendment — “subject to the jurisdiction thereof” — to argue that because Wong’s parents were citizens of China at the time of his birth, they were subject to the jurisdiction of the emperor of China, making their son the subject of a foreign power as well.

The lawyers for Wong cited congressional debates to argue that the amendment’s authors intended for birthright citizenship to apply broadly. The exceptions made under the jurisdiction clause were very few: the children of foreign diplomats; hostile foreign forces occupying U.S. territory; and initially, some Native Americans (Congress extended citizenship to all Native Americans in 1924.)

Wong’s lawyers also had an important political insight: If Wong lost his case, the U.S.-born children of white European immigrants would also be denied citizenship.

It was unclear how the Supreme Court would decide the case. Two years before, in Plessy v. Ferguson, the court had endorsed the “separate but equal” doctrine, giving legal backing to the Jim Crow laws that segregated and disenfranchised Black Americans in the South for decades. The court had also upheld several Chinese exclusion laws.

After more than a year, the court, in a 6-2 vote, sided with Wong. In the decision, Justice Horace Gray explained that the 14th Amendment’s reference to “all persons” were words that were “restricted only by place and jurisdiction, and not by color and race.”

Since that ruling, birthright citizenship has generally been not just accepted, but also lauded as a symbol of the country’s commitment to a fundamental American value: that all people born in the United States are equal at birth, regardless of their race, religion, or the immigration status of their parents.

Still, there has been some dissent, especially lately, as the country has struggled with an influx of migrants.

The Trump administration’s lawyers have argued in recent court filings that birthright citizenship should extend to the children of noncitizens only if the parents are lawfully domiciled in the U.S., as Wong’s parents were at the time of his birth.

The lawyers have also said that immigrants in the country illegally and people on temporary visas, like tourists and students, retain political allegiances to foreign governments and are thus “subject” to their “jurisdiction,” making their U.S.-born children ineligible for automatic U.S. citizenship.As for Wong, after his victory in court, he — like many Chinese Americans — continued to face lengthy interrogations from federal immigration officials to prove that he was a citizen.

Eventually, he moved to China.