The Constitution doesn't bar non-citizens from voting, but when San Francisco opened up school elections to all residents, a conservative firestorm followed.
The Supreme Court rejected the reasoning behind the administration's proposed addition of the question, so the president would need to provide a new rationale.
Non-citizens in the military are now denied citizenship more frequently than their civilian counterparts. The Department of Defense appears to be behind the shift.
The five conservatives on the court seemed ready to rule against three lower courts, a collection of researchers and experts, and five former leaders of the Census Bureau.