Activists and civil rights groups have spent more than a year quelling immigrant communities’ fears around the census — only to have President Donald Trump issue a memorandum to exclude undocumented immigrants from census results.

That has caused simmering concerns about the politicization of the census process to boil over for civil rights groups and congressional Democrats. House Oversight and Reform Chairwoman Carolyn B. Maloney said she plans to hold an emergency hearing on the memorandum next week.

“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,” the New York Democrat said in a statement.

Tuesday’s memorandum has already attracted legal scrutiny. On Wednesday, a Maryland federal judge ruled that litigants challenging Trump’s order last year to collect citizenship information could add the memo to their suit.

Census results don’t just determine how many of the 435 House seats each state gets. They guide more than $1.5 trillion in federal spending annually and guide thousands of decisions made by businesses and state and local governments.

The national response rate stands at more than 62 percent, but it is considerably lower in areas with large minority populations such as major cities and Native American reservations. The counting effort has been complicated by the ongoing coronavirus pandemic as well as lingering fears over Trump’s failed attempt to add a citizenship question to the 2020 census.

Michael Toledo, who leads the nonprofit Centro Hispano in Reading, Pennsylvania, said his group spent months encouraging people to respond to the census, particularly families with at least one undocumented member.

“Given all the rhetoric, the unfortunate rhetoric that we had heard throughout the federal level, regarding asking questions on the census regarding citizenship … it caused a lot of people in our community to be afraid to complete the census, to not want to complete the census for fear of retaliation,” Toledo said.

Tuesday’s memorandum may complicate those efforts, according to advocacy groups. Common Cause President Karen Hobert Flynn said in a statement Tuesday that the memo was “a blatant attempt to skew how electoral districts are drawn, instill fear and chaos in immigrant communities, and send a message to his white supremacist base.”

This decade, the Census Bureau’s own planning documents cited a heightened level of government mistrust that may discourage people from responding to the census. Tuesday’s memorandum won’t help, said former Census Bureau director Kenneth Prewitt, who oversaw the 2000 census. 

Prewitt said the agency has relied on its nonpartisan, professional nature to encourage people to respond. Trump’s actions — from the citizenship question battle, to adding more political appointees to the agency, to Tuesday’s order — may cast a “long shadow” over counting efforts, he said.

“Once you begin to eat away at public trust, the legitimacy of the census itself, it is going to take a long time to build up that trust again,” he said.

Prewitt pointed out that census officials fought mistrust for decades over the use of the 1940 census data that helped identify Japanese Americans for internment during World War II.

Advocates have pushed back on the counting process since Trump attempted in 2018 to add a citizenship question to the census. While Trump dropped the question after a Supreme Court ruling last year, surveys by the National Association of Latino Elected and Appointed Officials and other groups found a significant portion of immigrant communities remain discouraged from participating in the census.

Another former Census Bureau director, John Thompson, said this year’s census problems may not be on the same level as those surrounding the 1940 results, but he acknowledged the memorandum may generate some distrust. He also emphasized that census responses are still safe and private under federal law.

“I think it is going to raise a perception that the data would not be used appropriately, that the data would not be safe,” Thompson said. “But you can’t write an executive order or memorandum that would trump [privacy law.]”