As immigrants and their families continue to grapple with Donald Trump’s intent to end birthright citizenship, one Chinese-American’s 1898 case makes the prospect of such a move not so simple.

Wong Kim Ark, a restaurant cook who was born in San Francisco, was barred from reentering the U.S. after a trip to visit his parents in China. Wong was arrested, and his case eventually made it to the Supreme Court, where judges ruled that under the 14th Amendment, anyone born in the U.S. is automatically a citizen.

Though Trump claimed he could sign an executive order to revoke the current birthright citizenship policy, Wong’s case set a precedent that’s remained the law of the land for more than a century. In fact, the policy could likely only be changed through a constitutional amendment.

“The bigger issue for us as a country is how do we create more pathways to citizenship, not whether we should cut it off,” Aarti Kohli, executive director of Advancing Justice ― Asian Law Caucus, told HuffPost. We have a lot of people who already call America home who should have the opportunity to become citizens.

Department of Justice/National Archives Wong Kim Ark, a cook born in San Francisco, was barred from reentering the U.S. after visiting his parents in China.

Wong’s parents had arrived in the U.S. from China during a time of fierce anti-Chinese sentiment. The era had birthed the Chinese Exclusion Act, legislation that put a 10-year moratorium on Chinese labor immigration. The act also barred courts from granting Chinese immigrants citizenship.

Wong’s parents came to the country seeking U.S. citizenship but eventually left after the act had cut off any pathway to citizenship status. They had also feared the vigilante violence that often targeted Chinese immigrants at the time. In fact, one of the largest lynchings in American history occurred in 1871. Hundreds had descended upon Los Angeles’ Chinatown, and the mob lynched an estimated 17 to 20 Chinese immigrants.

But Wong himself had a life in the United States, and, though he had traveled to China before and had been readmitted into the U.S. without any issues, his 1895 trip presented a host of problems. Authorities ordered the Chinese-American to return to the ship.

Chinese immigrant aid organization Six Companies stepped in to provide Wong legal help. Wong’s lawyer, Thomas D. Riordan, argued that the cook’s reentry into the U.S. was protected under the 14th Amendment. As the case escalated to federal court, immigration hard-liners fought back, claiming Wong’s “accident of birth” didn’t mean citizenship.

In the end, the U.S. Supreme Court ruled in favor of Wong.

“If the Trump administration issued an executive order, it would be immediately challenged in the courts, and judges would likely rely on Wong Kim Ark to find the executive order unconstitutional,” Kohli said.

Many conservatives and even officials appointed by Trump himself disagree with the president’s stance on birthright citizenship.

“The plain meaning of this language is clear,” James Ho, whom Trump appointed as a federal appeals court judge, wrote in 2011 of the 14th Amendment.

Ho, then a solicitor general of Texas, wrote that “a foreign national living in the United States is ‘subject to the jurisdiction thereof’ because he is legally required to obey US law.”

House Speaker Paul Ryan (R-Wis.) addressed Trump’s comments, telling a Kentucky radio station earlier this week that “you cannot end birthright citizenship with an executive order” ― to which Trump responded that Ryan “knows nothing about” birthright citizenship.

Kohli pointed out that those who oppose birthright citizenship are in the minority.

“It’s clear that most Americans have embraced birthright citizenship and believe that anyone who is born here should have the right to be a citizen. A few political leaders are trying to further a white supremacist agenda and create a ‘fix’ to a problem that doesn’t exist,” she said.

What’s more, “Many scholars have noted that birthright citizenship has helped the U.S. integrate each new wave of immigrants as their children are recognized as U.S. citizens.”

Clarification: A previous version of this story indicated a lynching in Los Angeles’ Chinatown in 1871 was the largest in American history. While it was one of the largest, it is not clear that it is in fact the largest.