In the first—but surely not the last—court order temporarily blocking President Donald Trump‘s executive order on birthright citizenship, Reagan-appointed Judge John Coughenour said he could not “remember another case where the question presented is as clear as this one.”

He’s right. In the executive order attacking the constitutional guarantee of birthright citizenship, Trump is making the same arguments that the framers of the 14th Amendment heard and explicitly rejected more than 150 years ago. The 14th Amendment’s Citizenship Clause promises, very simply and clearly, that “all persons born or naturalized in the United States” are citizens, regardless of national origin or status of their parents. There are many constitutional questions where the text and history are complicated. This isn’t one. All means all.

The guarantee of birthright citizenship goes back centuries, but the need for the United States to codify the rule became necessary after Dred Scott v. Sandford, the infamous 1857 Supreme Court decision denying the citizenship—and attendant constitutional rights and protections—of African Americans. The ensuing fight over the meaning of our Constitution was fought on the battlefields of the Civil War and in the halls of Congress. After the Civil War, a hard-won new vision of our Constitution emerged in rebuke of Dred Scott: all people born or naturalized in this country would be entitled to citizenship, equally American at birth.

During the congressional debates over the 1866 Civil Rights Act, which included a nearly identical citizenship provision, some members of Congress worried that birthright citizenship would apply to the children of new immigrants from Asia and Europe: could birthright citizenship “have the effect of naturalizing the children of the Chinese and Gypsies born in this country[?]” The victorious supporters of birthright citizenship agreed it would—”undoubtedly”—and that was a great thing.

The framers of the 14th Amendment made sure that the guarantee of birthright citizenship was enshrined in the Constitution so that it would be protected from the worst impulses of politicians. A constitutional guarantee cannot be taken away by an executive order or an act of Congress. Only a constitutional amendment can change the Constitution. As the federal judge who has temporarily blocked the order from taking effect explained, Trump’s executive order is so “blatantly unconstitutional” that it “boggles my mind” that any member of the bar would defend it.

Unfortunately, then and now, there were still attempts to constrict the promise of birthright citizenship. The Supreme Court has rejected them all. For example, in the 1898 case Wong Kim Ark v. United States, a young Californian named Wong Kim Ark visited family in China, then tried to return to the United States. Immigration officials claimed that he could not reenter the country because under the racist Chinese Exclusion Act, Wong’s parents could never become citizens, so Wong himself could not be a citizen. The Supreme Court rejected that interpretation and held that because Wong was born in the United States, he was clearly an American citizen under the Citizenship Clause.

Trump’s desperate attempts to define away this constitutional promise have already been rejected before. The 14th Amendment’s Citizenship Clause has a narrow exception for those not “subject to the jurisdiction” of the United States. The exception couldn’t be much narrower: it applies to the children of foreign officials with diplomatic immunity, and children born to enemy combatants of hostile, occupying armies. Trump’s executive order attempts to stretch this language to cover broad categories of immigrants. This misreading has already been rejected by the courts time and time again. For example, in the 1982 Plyler v. Doe case, the Supreme Court rejected the argument that undocumented people were not subject to the jurisdiction of the United States. Voices across the ideological spectrum have long agreed that the guarantee of birthright citizenship is as clear as it is expansive.

For more than 150 years, our Constitution has protected all persons born or naturalized here, whether their parents were enslaved or free, rich or poor, whether they came over on the Mayflower or whether they were recent immigrants. Trump’s attack on our Constitution is an attempt to take us back to some of our nation’s darkest days before the Civil War.

Courts should continue to quickly reject his absurd, insulting, and ahistorical legal arguments, which violate the clear text of the 14th Amendment. They could never hold up in a courtroom, but they are meant to instill fear in our communities and send the reprehensible message that the children of immigrants cannot be real Americans. At a time when our friends and families in immigrant communities are facing lawless intimidation, We the People must speak out about the true promise and protection of the Constitution.