President Donald Trump has invoked executive privilege in an attempt to block Congress from documents about how a citizenship question came to be added to the 2020 census.

Joining Boston Public Radio to weigh in on this topic was homeland security expert Juliette Kayyem. Kayyem is on the faculty of Harvard’s Kennedy School and a CNN analyst.

"The question was always: What was motivating the Trump administration for doing this? They claimed it was for data-gathering purposes," Kayyem said Wednesday.

That claim is reportedly contradicted by evidence found recently in the files of a Republican gerrymandering expert, Thomas Hofeller, which suggests the question was intended to "create a structural electoral advantage for, in [Hofeller's] own words, ‘Republicans and Non-Hispanic Whites,'" according to lawyers mounting a legal challenge to the question.

"There are emails that literally [say] ... it will suppress the black and brown vote, in their words, not mine," Kayyem said.

Kayyem says the question's impact on the census could have real consequences. Experts warn it could lead to the most significant undercount of black and Latinx people in 30 years.

"This is actually going to impact the next 10 years and how we assess ... the distribution of funding, the distribution of resources," Kayyem said.