A fundraising email that President Donald Trump’s reelection campaign sent supporters on Monday asking them to support adding a citizenship question to the 2020 Census triggered left-wing activists. They are even claiming that Trump’s campaign is assaulting the Constitution.

“The President wants the 2020 United States Census to ask people whether or not they are citizens,” the email read. “The President wants to know if you’re on his side.”

Arturo Vargas, executive director of the National Association of Latino Elected and Appointed Officials’ (NALEO) Educational Fund, told the Washington Post that the email was “demoralizing” and “an assault on the constitution.”

“The fact that the Trump campaign would start using this as a fundraiser just really is an assault on the constitution,” which mandates as accurate a count as possible,” Vargas said. “It plays to the anti-immigrant nativist sentiments that the Trump campaign used to get elected, and it’s a way to keep that kind of statement alive as the president goes into his second year.”

Vanita Gupta, president and CEO of the Leadership Conference on Civil and Human Rights, told the Post that the email casts “doubt on the Justice Department’s stated reasons for proposing this untested question at the 11th hour.”

“We now know that support for adding a citizenship question to the 2020 Census goes all the way up to President Trump,” she reportedly said.

In December, the Justice Department sent a letter to the Census Bureau asking for a citizenship question to be included in the next Census so it can better enforce the Voting Rights Act.

“This data is critical to the Department’s enforcement of Section 2 of the Voting Rights Act and its important protections against racial discrimination in voting,” the letter read. “To fully enforce those requirements, the Department needs a reliable calculation of the citizen voting-age population in localities where voting rights violations are alleged or suspected.”

Trump campaign fundraising off of proposed addition of citizenship question to 2020 census, which would almost certainly make the decennial census both more expensive and less accurate. pic.twitter.com/u5SKFHLlID — Catherine Rampell (@crampell) March 19, 2018

This is nuts. Citizenship question hasn't been asked since 1950 & would massively suppress responses among immigrants experts say https://t.co/FV0ZYhS0SE https://t.co/GmZaoS6d5S — Ari Berman (@AriBerman) March 19, 2018

Kansas Secretary of State Kris Kobach recently argued in Breitbart News that adding the citizenship question matters because “the very principle of one person, one vote, is at stake.”

“Right now, congressional districts are drawn up simply based on the number of warm bodies in each district. Not only are legal aliens counted, but illegal aliens are counted too. As a result, citizens in a district with lots of illegal aliens have more voting power than citizens in districts with few illegal aliens,” Kobach wrote. “Think of it this way. There are about 710,000 people in each congressional district. But, if half of the district is made up of illegal aliens, then there are only 355,000 citizens in the district. The value of each citizen’s vote in such a district is twice as high. That is unfair.”

The Census Bureau must finalize its questions by March 31 and send them to Congress. Ahead of the deadline, Democrats in the House and Senate, past census directors, and left-wing attorneys general have all lobbied to have the citizenship question removed.