President Trump signed a memo Tuesday intended to prevent undocumented immigrants from being counted in the 2020 census. But it’s unclear how this would be accomplished, as the census questionnaires were distributed in March without a citizenship question. The Trump administration had campaigned to include a question on the census asking individuals’ citizenship status for the first time in 60 years, but the Supreme Court blocked it from being added. Census results are used to evaluate the number of seats each state is allocated for the House of Representatives and affects the disbursal of federal funds. The Constitution requires that a census be conducted of “persons” living in the country, but doesn’t specify that they must be citizens. Lower courts have previously ruled that undocumented immigrants should be counted in the census.