When President Trump and his minions attack the Census, they are messing with the US Constitution and the better angels of the American experiment. This is no small matter. And this is no small fight. Progressives should understand it as such and respond accordingly—not merely with a strong defense but with an even stronger offense.

It is not enough to leave this one to the courts or the Census Bureau. Yes, the Supreme Court has delivered a smackdown to the administration’s scheme to add a citizenship question to the survey. And, yes, the administration appeared to signal last week that it was backing down when it allowed the printing of Census forms to begin. But appearances can be deceiving, especially with this president. Trump is now asserting that, no matter what courts and law and printing deadlines may say, he’s still interested in getting the citizenship question into the mix. So the advocates for a full and fair count must be prepared to defend the ground that has been gained. Congressman Jamie Raskin, the Maryland Democrat who chairs the subcommittee on civil rights and civil liberties of the House Oversight and Reform Committee, offers wise counsel when he says that “right-wing attacks on democracy never sleep, so we must all remain vigilant.”

Yet progressives must, at the same time, go on the offensive, promoting an understanding of the Census as what it is: “a cornerstone of our democracy.”

That is how a group of Democratic senators described the Census this week in a letter urging the administration to end efforts to “delay and jeopardize the Census Bureau’s ability to conduct a full, fair, and accurate decennial census as required by the U.S. Constitution and the Census Act.”

That intervention by the senators was necessary, even after the high court ruled against the administration. The attempt by Trump and his allies to add the “citizenship” question to the 2020 Census is just one of the threats posed by conservative charlatans who seek to game the processes of the federal government for political benefit. But it is a particularly serious one, and that is why it has been advanced so desperately—and dishonestly—by the administration aides who last week were publicly shamed by the high court.

The assessment of the Court’s decision from Vermont Senator Bernie Sanders was as blunt as it was accurate. “Trump lied about his motivations, and five justices called him on it,” said the Democratic presidential contender. “His proposal to add a citizenship question to the census was nothing but a racist attempt to disenfranchise communities of color.”

The lies that Secretary of Commerce Wilbur Ross and others told about the citizenship question were part of a dangerous political game that exploited vulnerabilities of a project that James Madison warned could be undone by partisan factions that “are united and actuated by some common impulse of passion or interest, adverse to the rights of other citizens or to the permanent and aggregate interests of the community.”

From the start of what has now become his permanent campaign, Trump has imagined presidential powers that do not exist. And he has invited Americans to do the same, exploiting the fact that a lot of what people think is in the Constitution is not there. The founding document did not mention democracy, and it certainly did not outline universal voting rights. It did not propose political parties, primary elections or—and this may surprise Mr. Trump—the monarchical flight of fantasy that is “executive privilege.” But it did mention the Census. Right up at the top, in Article 1, Section 2, the document requires that an “enumeration shall be made” within successive terms of 10 years. Practically, what that means is that since 1790 the federal government has organized a decennial counting of the people.

The point of this enumeration is a radical and democratizing one. The founders of the American experiment, who had experienced colonial abuses that included taxation without representation, developed strategy for counting every American and using the results to establish representative democracy.

“Enshrining this invention in our Constitution marked a turning point in world history,” explains the Census Bureau. “Previously censuses had been used mainly to tax or confiscate property or to conscript youth into military service. The genius of the Founders was taking a tool of government and making it a tool of political empowerment for the governed over their government.”

The Census is a protection against “the enemies to public liberty” that the wisest of the founders feared might import to the new United States the kingly privileges and abuses against which the American Revolution was waged. The promise of representative democracy was not realized in the founding moment, or for decades, even centuries, after the Constitution was written. Sexism, racism, slavery, segregation, poll taxes, and biases against urban centers erected barriers to universal suffrage and governance that reflected the will of the people. Even now, at a point when many of the old barriers have been removed, a new generation of Tories scheme to suppress the vote.

Few suppressions could be so severe as a mangling of the Census. That’s the reason why civil rights, civil liberties, and democracy groups rallied to prevent the addition of the “citizenship” question, which they warned would lead to confusion, fear, and a severe undercount. This rallying of the forces of democracy has been strikingly successful. But it cannot be the end of anything. It must be the beginning.

Now, a full count is possible, and it must be pursued aggressively by progressives.

The Census is about much more than numbers. It is about empowerment.

This is the reason why we should honor Massachusetts Senator Elizabeth Warren’s call to action. “The Census must count every person,” says Warren. “Our Constitution demands it. Our democracy requires it.”