The Commerce Department announced Monday that it would include a question regarding citizenship on the 2020 Census.

Many lawmakers and advocates worry the move could lead to an inaccurate count of immigrants in the US.

A statistically significant miscount in the census could hurt academic research, business decisions, and the federal allocation of funds.

The US Commerce Department announced Monday that the 2020 Census would include a new question on citizenship, a tweak that could send shockwaves through the world of politics and economics.

The department said the census would ask whether respondents are US citizens.

The Trump administration says the addition will help properly enforce the Voting Rights Act. But immigration advocates and many lawmakers expressed concern that it could undercount immigrants, particularly those in the US illegally, thus distorting the population count.

"An accurate count of everyone living in the United States is vital to our democracy," said Sen. Dianne Feinstein, the top Democrat on the Senate Judiciary Committee. "Adding a question designed to depress participation in certain communities is an assault on the foundations of this country."

The attorneys general of New York and California have already said they plan to sue the Trump administration to remove the question.

Beyond the legal question — the Constitution says the census should be an accurate count of people living in the US regardless of citizenship — any miscount could also have serious consequences for state agencies, economists, and academics.

Here's a rundown of what the change could affect: