WASHINGTON – President Donald Trump signed a memorandum Tuesday claiming that undocumented migrants should not be counted in the census for purposes of deciding how many members of Congress are apportioned to each state – though the practical impact of the president’s expected move is uncertain at best.

“Respect for the law and protection of the integrity of the democratic process warrant the exclusion of illegal aliens from the apportionment base, to the extent feasible and to the maximum extent of the President’s discretion under the law,” Trump said in the brief document.

The memo, which the White House presaged for months, will almost certainly draw legal challenges just as an earlier effort by Trump to add a citizenship question to the 2020 census prompted a court battle that went to the Supreme Court, an effort the president lost.

Trump backed down from adding the citizenship question last year.

The memo does not say how the U.S. Census Bureau could distinguish citizens from non-citizens – for any reason – because counters are prohibited from asking a citizenship question. Apportionment is the process of deciding how many members of the House of Representatives members each state will receive based on that state’s population.

Elizabeth Wydra, president of the Constitutional Accountability Center, said Trump’s demand is “blatantly unconstitutional” because it amounts to not counting undocumented people in the census at all.

“The federal government has a constitutional obligation to count all people living in the United States,” she said, “whether they are citizens or noncitizens, whether they were born in the United States or in a distant part of the world.”

Legal analysts said Trump’s effort to essentially discount immigrants in the country illegally for purposes of reapportionment is already a dead letter, citing a Supreme Court decision from last year blocking the president’s attempts to add a citizenship question to the census.

“The Constitution says count ‘persons’ not citizens,” tweeted Joyce Alene, a law professor at the University of Michigan. “His unconstitutional EO today, directing a count of only citizens is red meat for his base & an effort to distract from Covid & his other disasters.”

In a written statement issued by the White House, Trump said his memo reflects “a better understanding of the Constitution.”

In a more political vein, Trump – who trails Democratic challenger Joe Biden in numerous pre-election polls – said “the radical left” is trying to “conceal the number of illegal aliens in our country.” He also claimed “a broader left-wing effort to erode the rights of Americans citizens, and I will not stand for it.”

Census takers are prohibited from asking respondents whether or not they are U.S, citizens; it is hard to know how they can determine whether respondents are in the country illegally.

Joshua Geltzer, executive director of the Institute for Constitutional Advocacy and Protection, tweeted that the language of the Constitution, federal statutes, and Supreme Court precedent “makes Trump’s position outrageous.”

The American Civil Liberties Union said the “the Constitution requires that the Census count EVERYONE in the United States,” tweeted: “Reminder, we won at the Supreme Court last year against the administration’s last anti-immigrant Census scheme. If Trump issues this unconstitutional order, we’ll win again.”

Trump has served notice that he will make immigration a major issue in his re-election campaign, just as he did during his first run in 2016. Opponents said Trump is demonizing Hispanic migrants, and people of color in general, in a base appeal to white workers.

The coming legal battle echoes the one inspired by Trump’s failed attempt last year to add a citizenship question to the census.

In June 2019, the Supreme Court ruled against the citizenship question, saying the Trump administration’s reasons for wanting to include it in the census appeared to “have been contrived.”

Trump said he thought about ordering the question anyway, but decided against. Instead, he ordered government agencies to obtain citizenship data by reviewing existing databases and documents.

“We are not backing down on our effort to determine the citizenship status of the United States population,” Trump said a year ago.

Trump cited that 2019 order in his new memo on apportionment.

“Last summer in the Rose Garden, I told the American people that I would not back down in my effort to determine the citizenship status of the United States population,” Trump said. “Today, I am following through on that commitment.”