On the evening of March 26, Commerce Secretary Wilbur Ross announced that the 2020 census would reinstate a question on the decennial census that asks respondents whether or not they are citizens.

The announcement triggered an apoplectic reaction on the Left. Democrats in Congress such as Sen. Diane Feinstein (D-CA) and Minority Leader Nancy Pelosi (D-CA) expressed their outrage at the notion that the United States would want to know how many citizens it actually has. Even former Attorney General Eric Holder chimed in, calling the question a “direct attack on our representative democracy.” Meanwhile, most Americans were probably surprised to learn that the question wasn’t already on the census.

As usual, the Left did what they always do when they are upset about something – they filed a lawsuit. California’s attorney general Xavier Beccera filed a lawsuit the next day alleging that it was unconstitutional to even ask the question on the census. New York’s Attorney General Eric Schneiderman said that another suit would be forthcoming.

As I explained in an earlier column, it is essential that the United States know how many citizens it has. That information enables secretaries of state, who administer elections in most states, to determine exactly what percentage of eligible citizens are registered to vote. It also enables the U.S. Department of Justice to better enforce the Voting Rights Act.

Equally important, adding the citizenship question to the census will allow a future Congress, if it so chooses, to stop counting illegal aliens in the apportionment of congressional seats.

Because we currently count illegal aliens in apportioning seats, there are grossly different numbers of citizens in different districts. There are about 710,000 warm bodies in each congressional district. But some districts have large numbers of illegal aliens. For example, it is estimated that the 7th congressional district in Arizona – that of Rep. Ruben Gallego’s (D) – has just 379,000 U.S. citizens who are eligible to vote. The value of each citizen’s vote in such a district is twice as high as in districts where there are not so many illegal aliens.

Counting illegal aliens also allows a state with millions of illegal aliens to unfairly inflate the number of congressional seats and electoral votes it has. Indeed, if the leadership of the state has little regard for the rule of law – as is the case in California – it creates a perverse incentive for the lawless state to invite more illegal aliens to come in. Placed in this perspective, California’s sanctuary state law can be seen for what it is – a move to amass political power at the expense of the other states.

Which is why California’s liberal leadership is fighting so hard to stop the Census Bureau from even asking the question. Fortunately for the rest of us, California’s legal arguments don’t hold water.

California claims that it’s unconstitutional to even ask the citizenship question. However, the Framers of the Constitution would disagree. The citizenship question was asked on the census, in one form or another, from 1820 to 1950. James Madison and many of the other Framers were still alive in 1820. Indeed, Madison’s presidency lasted until March of 1817. If it had been unconstitutional to ask the citizenship question in 1820, one would have thought that the Father of the Constitution and his colleagues might have objected.

But of course counting the number of citizens, as distinct from aliens, has always been a core purpose of the census. In fact, the 1820 census sought to do exactly what the 2020 census will do – figure out both the number of citizens and the number of aliens living in the United States. The 1820 census distinguished the number of citizens from the “number of foreigners, not naturalized” in each household.

California also argues that since the Constitution requires apportionment according to the “whole number of free persons” residing in the country, all warm bodies in the country must be treated equally in apportioning seats. This argument is nonsense. An illegal alien is not a resident of the United States in any meaningful sense. His presence is a violation of law; and he can be deported at any time. If California’s argument were correct, then the troops of an invading army would also have to be counted in the census. In other words, if the 1810 census had been conducted in 1812, Congress would have had to count the invading British forces in allocating congressional seats.

The California lawsuit also contends that asking the citizenship question will scare aliens, causing them not to respond to the census. This argument too is bogus. In announcing the decision to reinstate the citizenship question, the Commerce Secretary Wilbur Ross pointed out that there is no empirical evidence supporting such a claim. Indeed, the Census Bureau has been asking the same citizenship question (as well as more detailed questions about where a person was born) on the American Community Survey for years. Yet the Left has never complained that it scares people away.

Moreover, the federal government is prohibited from using census answers against anyone, and the census form itself states very prominently that a person’s answers “are protected by law.”

In short, California’s arguments are weak, and the lawsuit is a loser. The federal government will prevail, if not in the district court, then on appeal. But the ferocity of the backlash from the Left demonstrates just how important the citizenship question is. America’s willful ignorance concerning the number of citizens and the number of aliens in the country must end.

Kris W. Kobach is the elected secretary of state of Kansas. An expert in immigration law and policy, he coauthored the Arizona SB-1070 immigration law and represented in federal court the ten ICE agents who sued to stop President Obama’s 2012 DACA amnesty. During 2001-03, he was Attorney General John Ashcroft’s chief adviser on immigration law at the Department of Justice. He is also a 2018 candidate for the office of governor of Kansas. His website is kriskobach.com.