Under the leadership of Attorney General Jeff Sessions, President Donald Trump’s Justice Department has repeatedly turned its back on our Constitution’s promise of an inclusive democracy, seeking to make it harder for citizens to exercise their right to vote. Now, the department has another trick up its sleeve. If successful, its ploy would undermine the fabric of our representative democracy for the next 10 years, and possibly beyond.

The Justice Department has requested that a mandatory citizenship question be added to the 2020 census. This would chill participation by immigrants across the country and result in bad data, biasing congressional apportionment, redistricting and funding decisions for an entire decade.

The Constitution imposes a clear duty on the Census Bureau: It requires a count of all people living in the United States, whether they are citizens or noncitizens, whether they were born in the United States or in a distant part of the world.

More than two centuries ago, our founders established a democracy premised on the idea that all people — no matter where they are from — deserve equal representation. To ensure a proper count of the nation’s population, the Constitution explicitly requires an “actual Enumeration” of the people. The census was the framers’ insurance policy against partisan efforts to manipulate the ground rules of our representative democracy.

Over the course of our nation’s history, the American people have made our Constitution’s representative democracy more inclusive. The original Constitution’s promise of equal representation for all persons was undermined by the Three-Fifths Clause, which provided that for the purpose of determining representation in Congress, someone who was enslaved would be counted as three-fifths of a person.

During the debates over the 14th Amendment, which ensured equal protection under the law, many in Congress sought a drastic change in our constitutional principles of equal representation, arguing that only citizens or voters should be counted in determining representation.

The framers of the 14th Amendment decisively rejected those arguments. They insisted that the entire immigrant population should be counted as part of the “We the People.” As history shows, the purpose of the census required by the Constitution has never been to count citizens but rather to count all the people of the nation.

Adding a mandatory citizenship question would be an end run around the Constitution. As the Census Bureau’s latest data reflects, if all persons were asked about citizenship status on the Census short form, participation in the census by immigrants and those living with immigrants would plummet.

Failing to count all people in the United States — as our Constitution requires — would be immensely damaging. The constitutionally mandated national count of the people determines how many members of Congress each state will elect, how many votes each state will have in the Electoral College, and how state, local and congressional districts will be drawn. The federal government also uses census figures to allocate billions of dollars in funding to local communities.

The Department of Justice claims that a citizenship question is necessary to ensure compliance with the Voting Rights Act, but this is transparently false. Since the passage of the Voting Rights Act in 1965, the short form census or the census questionnaire has never asked the American people to report their citizenship. A mandatory question on citizenship has never been necessary to ensure robust protection for the right to vote.

This is a specious justification for undercutting what the Constitution mandates: a count of all the people.