President Donald Trump on Tuesday directed the U.S. Secretary of Commerce to exclude undocumented immigrants from the numbers that will be used to determine Congressional representation following the 2020 Census, an order that Massachusetts Secretary of State William Galvin said is “absurd” and “an almost unprecedented effort to politicize the Census.”

The memorandum Trump signed early Tuesday afternoon does not specifically prevent non-legal residents from being counted during the Census but orders that undocumented immigrants not be included when it comes time for apportionment, the process of determining how many members of the House of Representatives each state gets based on its population.

“Excluding these illegal aliens from the apportionment base is more consonant with the principles of representative democracy underpinning our system of Government. Affording congressional representation, and therefore formal political influence, to States on account of the presence within their borders of aliens who have not followed the steps to secure a lawful immigration status under our laws undermines those principles. Many of these aliens entered the country illegally in the first place,” the memo reads. “Increasing congressional representation based on the presence of aliens who are not in a lawful immigration status would also create perverse incentives encouraging violations of Federal law. States adopting policies that encourage illegal aliens to enter this country and that hobble Federal efforts to enforce the immigration laws passed by the Congress should not be rewarded with greater representation in the House of Representatives.”

Approximately 185,000 undocumented immigrants are in Massachusetts, the Massachusetts Budget and Policy Center estimated last year.

The U.S. Constitution calls for a count of all “persons” in each state every 10 years and the 14th Amendment specifies that seats in the U.S. House of 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.” But it is a final report from the president, not simply each state’s Census count, that is used to calculate representation in the U.S. House.

In the memo signed Tuesday, the Trump administration contends that ”[t]he Constitution does not specifically define which persons must be included in the apportionment base” and that the “discretion delegated to the executive branch to determine who qualifies as an ‘inhabitant’ includes authority to exclude from the apportionment base aliens who are not in a lawful immigration status.”

Galvin said Tuesday that the historical references and reasoning in Trump’s memo are “so replete with errors … he must not have done well in elementary civics,” and said the political motivation behind Tuesday’s order is obvious, given the administration’s previous attempts to make citizenship status part of the Census.

“The Census, throughout our history, has always been an accurate, even count. That’s what it’s been irrespective of which party controlled Congress, controlled the presidency, and he clearly has no such qualms about accuracy or honesty,” he said. “He basically wants to try to rig the Census, and I think he’s trying to play to his political base. But if he were allowed to proceed he would certainly be trying to diminish the representation in areas that have significant populations of non-citizens.”

Last year, the U.S. Supreme Court blocked the Trump administration from asking about citizenship on the Census but the president on Tuesday suggested his administration will still be able to distinguish citizens from non-citizens because he, in an executive order signed last July, “instructed executive departments and agencies to share information with the Department of Commerce, to the extent permissible and consistent with law, to allow the Secretary to obtain accurate data on the number of citizens, non-citizens, and illegal aliens in the country.”

The Trump administration’s latest proclamation on the Census comes at a critical time in the effort to count every person in the country, Galvin said. To date, 64.2% of Massachusetts households have responded to the Census, leaving about a third of residents so far uncounted.

“We’re now doing the follow-up on communities that have not responded in higher percentages. So, for instance, in Massachusetts the communities that this most affects … are communities that are undercounted already,” he said. “Lawrence, Chelsea, Boston, Worcester, and oftentimes these are the places where people who are residents are non-citizens. So it’s coming at a critical time, this is the time the bureau is supposed to be going door to door to count these people. The question is, is there going to be some kind of political interference from the administration in the Census.”

Galvin said he expects the memo signed Tuesday will result in litigation but said that Congress and specifically the House Oversight Committee should step in more immediately.

“They need to bring in the [Census] Bureau and make sure the bureau understands that whatever Trump says is irrelevant to counting every person,” the secretary said, adding that he planned to discuss the matter with U.S. Rep. Stephen Lynch, who sits on the Oversight Committee.

On Tuesday afternoon, the U.S House Oversight Committee announced that it will hold an emergency hearing on the Census next week and “is considering additional steps to respond to the President’s unconstitutional action.”

“Taking this step right in the middle of the ongoing Census is particularly egregious and sinister because it appears purposefully designed to depress the count, deter people from filling out their forms, and corrupt the democratic processes on which our nation is founded,” Oversight Committee Chairwoman Carolyn Maloney of New York said in a statement.

In the Census Bureau’s own “Final 2020 Census Residence Criteria and Residence Situations” document, the agency states that “foreign citizens are considered to be ‘living’ in the United States if, at the time of the census, they are living and sleeping most of the time at a residence in the United States.”

“The federal government has a constitutional obligation to count 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,” Elizabeth Wydra, president of the Constitutional Accountability Center, tweeted Tuesday afternoon.

In his own statement on the topic Tuesday, Trump said signing the memo represented him upholding his promise that he “would not back down in my effort to determine the citizenship status of the United States population” and said his administration’s action “reflects a better understanding of the Constitution.”

“There used to be a time when you could proudly declare, ‘I am a citizen of the United States.’ But now, the radical left is trying to erase the existence of this concept and conceal the number of illegal aliens in our country,” the president said. “This is all part of a broader left-wing effort to erode the rights of Americans citizens, and I will not stand for it.”

The American Civil Liberties Union, which took the Trump administration to court last year over its plan to include a citizenship question on the 2020 Census, tweeted Tuesday that it is confident that Trump’s latest Census-related action will also be overruled by the courts.

“His latest attempt to weaponize the census for an attack on immigrant communities WILL be found unconstitutional. We’ll see him in court – and win – again,” the organization said.