Raul A. Reyes is an attorney and member of the USA Today board of contributors. Follow him on Twitter @RaulAReyes . The opinions expressed in this commentary are solely those of the author.

(CNN) President Donald Trump's Justice Department is proposing a new question for the US Census that could throw a chill over the nation's decennial headcount.

According to new reporting from ProPublica , the Department of Justice wants to add a citizenship question to the 2020 Census. A DOJ official made this request to the bureau in a letter dated December 12. The l etter argues that the DOJ needs the citizenship data to protect minority populations from "racial discrimination in voting."

But does anyone seriously believe that Attorney General Jeff Sessions, head of the Department of Justice, is concerned about minority voting rights? His past indicates otherwise. He can frame his motivation for wanting citizenship information in worthy terms all he wants, but the reality is that such a change to the census could have far-reaching implications -- none of them good.

The proposed change goes against the longstanding mission of the census "to serve as the leading source of quality data about the nation's people and economy" and would politicize the critical decennial population count.

The full census typically asks questions about race, housing, marital status and other topics. It has not included a citizenship question since 1950. As to the proposed new question, according to the ProPublica report, "the DOJ declined to comment and the White House did not respond to a request for comment."

Asking about citizenship on the census would most likely lower the number of responses, particularly among Latinos and immigrants.

The importance of the census cannot be overstated. Data collected from the survey affect how congressional seats are apportioned and how federal funds are allocated to state and local governments. It affects the distribution of money for community necessities like services for senior citizens, roads and schools, and job training centers. That's what makes this potential move by the administration so troubling.

Since the census began in 1790, its goal has been to count all people, not just citizens. The 14th Amendment states, "Representatives shall be apportioned among the several States according to their respective numbers, counting the whole number of persons in each State, excluding Indians not taxed."

The founding fathers could have inserted the word "citizens" in this provision, as they did in other sections of the Constitution, but they did not. Clearly, their intent was that apportionment of representatives, which depends on census results, should be based on who is present in the country, period.

As recently as 2016, the Supreme Court unanimously ruled that election districts could be drawn based on total population, instead of the number of people eligible to vote. So any ideas that the Trump DOJ might have about collecting citizenship data -- with an eye toward changing how congressional districts are drawn -- would potentially undermine the spirit of that ruling.

But the most serious concern here is that asking about citizenship on the census would reduce the total numbers of responses. Thanks to Trump's often ugly rhetoric (such as referring to some Mexican immigrants as "rapists") and the actions of his administration (such as the cancellation of DACA), there is little trust between immigrants and the government.

The Pew Hispanic Center has noted that in 2010 there were an estimated 9 million "mixed-status" families in the United States — that is, families in which some members of a household are citizens and some are not. It is no stretch to imagine that such households would prefer to skip the census altogether rather than give the Trump administration information that could potentially be used to deport some of their loved ones.

In fact, fear among the immigrant population over the census has already been noted. In November, a government official warned that early test surveys showed that immigrants were wary of providing personal information to the government. The bureau's Mikelyn Meyers reported an "unprecedented groundswell in confidentiality and data-sharing concerns among immigrants or those who live with immigrants " related to the 2020 count -- and this was before news broke about the potential citizenship question.

What's more, Trump's Justice Department seems to be trying to get this citizenship question added at the last minute. ProPublica points out that new questions are "usually carefully field-tested, a process that can take years." Even then, problems still arise; the bureau has struggled for years to find the best way for Latinos to self-identify their race and ethnicity. And it doesn't exactly inspire confidence that the man Trump is considering to head the bureau, Thomas Brunell, has no government experience and once wrote a book called "Redistricting and Representation: Why Competitive Elections Are Bad for America."

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According to the ProPublica report, "The law governing the census gives the commerce secretary, currently Wilbur Ross, the power to decide on questions. They must be submitted to Congress for review two years before the census, in this case by April 2018. A census spokesperson said the agency will also release the questions publicly at that time."

Perhaps the Justice Department has legitimate reasons for wanting to know the number of citizens in the country. But it can get that information from the American Community Survey , which is conducted every year by the bureau and already asks about citizenship.

The bureau should be trying to formulate ways to build bridges with minority and immigrant populations, not taking actions that will scare off potential respondents. The Census Bureau should resist the DOJ's efforts to sabotage its work with an intrusive citizenship question. An accurate 2020 census count is essential for everyone living in the United States.