WASHINGTON — A request by the Justice Department to ask people about their citizenship status in the 2020 census is stirring a broad backlash from census experts and others who say the move could wreck chances for an accurate count of the population — and, by extension, a fair redistricting of the House and state legislatures next decade.

Their fear, echoed by experts in the Census Bureau itself, is that the Trump administration’s hard-line stance on immigration, and especially on undocumented migrants, will lead Latinos and other minorities, fearing prosecution, to ignore a census that tracks citizenship status.

Their failure to participate would affect population counts needed not only to apportion legislative seats, but to distribute hundreds of billions of dollars in federal money to areas that most need it.

“I can think of no action the administration could take that would be more damaging to the accuracy of the 2020 census than to add a question on citizenship,” Terri Ann Lowenthal, a consultant and leading private expert on census issues, said in an interview. “It would completely pull the rug out from under efforts to have everyone participate in the census as the Constitution envisions.”